Metallurgically prepared NiCu alloys as cathode materials for hydrogen evolution reaction

International Nuclear Information System (INIS)

Wang, Kunchan; Xia, Ming; Xiao, Tao; Lei, Ting; Yan, Weishan

2017-01-01

Ni−Cu bimetallic alloys with Cu content of 5, 10, 20, 30 and 50 wt% are prepared by powder metallurgy method, which consisted of powder mixing, pressing and sintering processes. The X-ray diffraction (XRD) measurement confirms that all the five Ni−Cu alloys possess the f.c.c. structure. The hydrogen evolution reaction (HER) activity of the prepared Ni−Cu alloy electrodes was studied in 6 M KOH solution by cathodic current-potential curves and electrochemical impedance spectroscopy (EIS) techniques. It was found that the electrocatalytic activity for the HER depended on the composition of Ni−Cu alloys, where Ni−10Cu alloy exhibited considerably higher HER activity than Ni plate and other Ni−Cu alloys, indicative of its chemical composition related intrinsic activity. - Highlights: • Ni−Cu alloys with various Cu contents were prepared by powder metallurgy method. • Ni−Cu alloy exhibits chemical composition related synergistic effect for HER activity. • Ni−10Cu alloy electrode presents a most efficient activity for HER. • Two time constants are observed in Nyquist curve and both of them related to the kinetics of HER.

Metallurgically prepared NiCu alloys as cathode materials for hydrogen evolution reaction

Energy Technology Data Exchange (ETDEWEB)

Wang, Kunchan; Xia, Ming [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Xiao, Tao [2nd Xiangya Hospital, Central South University, Changsha 410011 (China); Lei, Ting, E-mail: tlei@mail.csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Yan, Weishan [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China)

2017-01-15

Ni−Cu bimetallic alloys with Cu content of 5, 10, 20, 30 and 50 wt% are prepared by powder metallurgy method, which consisted of powder mixing, pressing and sintering processes. The X-ray diffraction (XRD) measurement confirms that all the five Ni−Cu alloys possess the f.c.c. structure. The hydrogen evolution reaction (HER) activity of the prepared Ni−Cu alloy electrodes was studied in 6 M KOH solution by cathodic current-potential curves and electrochemical impedance spectroscopy (EIS) techniques. It was found that the electrocatalytic activity for the HER depended on the composition of Ni−Cu alloys, where Ni−10Cu alloy exhibited considerably higher HER activity than Ni plate and other Ni−Cu alloys, indicative of its chemical composition related intrinsic activity. - Highlights: • Ni−Cu alloys with various Cu contents were prepared by powder metallurgy method. • Ni−Cu alloy exhibits chemical composition related synergistic effect for HER activity. • Ni−10Cu alloy electrode presents a most efficient activity for HER. • Two time constants are observed in Nyquist curve and both of them related to the kinetics of HER.

Fabrication of Ti-Ni-Cu shape memory alloy powders by ball milling method

International Nuclear Information System (INIS)

Kang, S.; Nam, T.

2001-01-01

Ti-Ni and Ti-Ni-Cu shape memory alloy powders have been fabricated by ball milling method, and then alloying behavior and transformation behavior were investigated by means of optical microscopy, electron microscopy, X-ray diffraction and differential scanning calorimetry. As milled Ti-Ni powders fabricated with milling time less than 20 hrs was a mixture of pure elemental Ti and Ni, and therefore it was unable to obtain alloy powders because the combustion reaction between Ti and Ni occurred during heat treatment. Since those fabricated with milling time more than 20 hrs was a mixture of Ti-rich and Ni-rich Ti-Ni solid solution, however, it was possible to obtain alloy powders without the combustion reaction during heat treatment. Clear exothermic and endothermic peaks appeared in the cooling and heating curves, respectively in DSC curves of 20 hrs and 30 hrs milled Ti-Ni powders. On the other hand, in DSC curves of 1 hr, 10 hrs, 50 hrs and 100 hrs, the thermal peaks were almost discernible. The most optimum ball milling time for fabricating Ti-Ni alloy powders was 30 hrs. Ti-40Ni-10Cu(at%) alloy powders were fabricated successfully by ball milling conditions with rotating speed of 100 rpm and milling time of 30 hrs. (author)

Giant magnetoresistance in melt spun Cu85Co10Ni5

DEFF Research Database (Denmark)

Curiotto, Stefano; Johnson, Erik; Celegato, Federica

2009-01-01

CuCoNi rapidly solidified alloys are interesting because they display giant magnetoresistance (GMR). In the present work a Cu85Co10Ni5 alloy has been synthesized by melt spinning and analysed for GMR. The ribbons obtained have been annealed at different temperatures and the evolution of the crystal...... structure with annealing has been studied by X-ray diffraction. The. ne microstructure has been observed by TEM and related to the magnetic properties, investigated in a vibrating sample magnetometer. In the studied composition the magnetoresistance was found to be lower than in binary CuCo alloys without...

Evolution of rapidly solidified NiAlCu(B) alloy microstructure.

Science.gov (United States)

Czeppe, Tomasz; Ochin, Patrick

2006-10-01

This study concerned phase transformations observed after rapid solidification and annealing at 500, 700 and 800 degrees C in 56.3 Ni-39.9 Al-3.8 Cu-0.06 B (E1) and 59.8 Ni-36.0 Al-4.3 Cu-0.06 B (E2) alloys (composition in at.%). Injection casting led to a homogeneous structure of very small, one-phase grains (2-4 microm in size). In both alloys, the phase observed at room temperature was martensite of L1(0) structure. The process of the formation of the Ni(5)Al(3) phase by atomic reordering proceeded at 285-394 degrees C in the case of E1 alloy and 450-550 degrees C in the case of E2 alloy. Further decomposition into NiAl (beta) and Ni(3)Al (gamma') phases, the microstructure and crystallography of the phases depended on the path of transformations, proceeding in the investigated case through the transformation of martensite crystallographic variants. This preserved precise crystallographic orientation between the subsequent phases, very stable plate-like morphology and very small beta + gamma' grains after annealing at 800 degrees C.

Chemical and electrical characterisation of the segregation of Al from a CuAl alloy (90%:10% wt) with thermal anneal

Energy Technology Data Exchange (ETDEWEB)

Byrne, C., E-mail: conor.byrne2@mail.dcu.ie [School of Physical Sciences, Dublin City University, Dublin 9 (Ireland); Brady, A.; Walsh, L.; McCoy, A.P.; Bogan, J. [School of Physical Sciences, Dublin City University, Dublin 9 (Ireland); McGlynn, E. [School of Physical Sciences, National Centre for Plasma Science and Technology, Dublin City University, Dublin 9 (Ireland); Rajani, K.V. [School of Electronic Engineering, Dublin City University, Dublin 9 (Ireland); Hughes, G. [School of Physical Sciences, Dublin City University, Dublin 9 (Ireland); School of Physical Sciences, National Centre for Plasma Science and Technology, Dublin City University, Dublin 9 (Ireland)

2016-01-29

A copper–aluminium (CuAl) alloy (90%:10% wt) has been investigated in relation to segregation of the alloying element Al, from the alloy bulk during vacuum anneal treatments. X-ray photoelectron spectroscopy (XPS) measurements were used to track the surface enrichment of Al segregating from the alloy bulk during in situ ultra-high vacuum anneals. Secondary ion mass spectroscopy (SIMS) indicates a build-up of Al at the surface of the annealed alloy relative to the bulk composition. Metal oxide semiconductor (MOS) CuAl/SiO{sub 2}/Si structures show a shift in flatband voltage upon thermal anneal consistent with the segregation of the Al to the alloy/SiO{sub 2} interface. Electrical four point probe measurements indicate that the segregation of Al from the alloy bulk following thermal annealing results in a decrease in film resistivity. X-ray diffraction data shows evidence for significant changes in crystal structure upon annealing, providing further evidence for expulsion of Al from the alloy bulk. - Highlights: • CuAl alloy (90%:Al 10% wt) deposited and vacuum annealed • XPS and SIMS data show segregation of Al from the alloy bulk. • Chemical changes seen indicate the reduction of Cu oxide and growth of Al Oxide. • Electrical measurements indicate a chemical change at the metal/SiO{sub 2} interface. • All data consistent with Cu diffusion barrier layer formed.

Disintegration of the net-shaped grain-boundary phase by multi-directional forging and its influence on the microstructure and properties of Cu-Ni-Si alloy

Science.gov (United States)

Zhang, Jinlong; Lu, Zhenlin; Zhao, Yuntao; Jia, Lei; Xie, Hui; Tao, Shiping

2017-09-01

Cu-Ni-Si alloys with 90% Cu content and Ni to Si ratios of 5:1 were fabricated by fusion casting, and severe plastic deformation of the Cu-Ni-Si alloy was carried out by multi-direction forging (MDF). The results showed that the as-cast and homogenized Cu-Ni-Si alloys consisted of three phases, namely the matrix phase α-Cu (Ni, Si), the reticular grain boundary phase Ni31Si12 and the precipitated phase Ni2Si. MDF significantly destroyed the net-shaped grain boundary phase, the Ni31Si12 phase and refined the grain size of the Cu matrix, and also resulted in the dissolving of Ni2Si precipitates into the Cu matrix. The effect of MDF on the conductivity of the solid solution Cu-Ni-Si alloy was very significant, with an average increase of 165.16%, and the hardness of the Cu-Ni-Si alloy also increased obviously.

Studies of the development and characterization of the Cu-Ni-Pt and Cu-Ni-Sn alloys for electro-electronic uses

International Nuclear Information System (INIS)

Silva, Luis Carlos Elias da

2006-01-01

The Cu and its alloys have different applications in the owed modern society the excellent electric properties, thermal conductivity, resistance to the corrosion and other properties. These applications can be in valves, pipes, pots for absorption of solar energy, radiators for automobiles, current driver, electronic driver, thermostats elements and structural parts of nuclear reactors, as, for example, reels for field toroidal for a reactor of nuclear coalition. The alloys used in nuclear reactors, we can highlight Cu-Be, Cu-Sn and Cu-Pt. Ni and Co frequently are added to the Cu alloys so that the solubility is moved for temperatures more elevated with relationship to the binary systems of Cu-Sn and Cu-Pt. The addition of Ni-Pt or Ni-Sn to the Cu in the same or inferior percentages to 1,5% plus thermomechanical treatments changes the properties of the copper. We studied the electric conductivity and hardness Vickers of the Cu-Ni-Pt and Cu-Ni-Sn and compared with the electrolytic Cu. In the proposed flowcharts, breaking of the obtaining of the ingot, we proceeded with thermo mechanical treatments. (author)

In situ observation of Cu-Ni alloy nanoparticle formation by X-ray diffraction, X-ray absorption spectroscopy, and transmission electron microscopy: Influence of Cu/Ni ratio

DEFF Research Database (Denmark)

Wu, Qiongxiao; Duchstein, Linus Daniel Leonhard; Chiarello, Gian Luca

2014-01-01

Silica-supported, bimetallic Cu-Ni nanomaterials were prepared with different ratios of Cu to Ni by incipient wetness impregnation without a specific calcination step before reduction. Different in situ characterization techniques, in particular transmission electron microscopy (TEM), X-ray...... diffraction (XRD), and X-ray absorption spectroscopy (XAS), were applied to follow the reduction and alloying process of Cu-Ni nanoparticles on silica. In situ reduction of Cu-Ni samples with structural characterization by combined synchrotron XRD and XAS reveals a strong interaction between Cu and Ni species......, which results in improved reducibility of the Ni species compared with monometallic Ni. At high Ni concentrations silica-supported Cu-Ni alloys form a homogeneous solid solution of Cu and Ni, whereas at lower Ni contents Cu and Ni are partly segregated and form metallic Cu and Cu-Ni alloy phases. Under...

Phase transformations behavior in a Cu-8.0Ni-1.8Si alloy

Energy Technology Data Exchange (ETDEWEB)

Lei, Q. [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China); Li, Z., E-mail: lizhou6931@163.com [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China) and Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Changsha, 410083 (China); Wang, M.P. [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China); Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Changsha, 410083 (China); Zhang, L.; Gong, S. [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China); Xiao, Z. [Department of Engineering, University of Liverpool, Liverpool, L693 GH (United Kingdom); Pan, Z.Y. [Hunan Nonferrous Metals Holding Group Co., Ltd., Changsha, 410015 (China)

2011-02-24

Research highlights: > High solute concentrations Cu-Ni-Si alloy with super high strength and high conductivity has a good prospect for replacing Cu-Be alloys. At least four different kinds of precipitation products (DO{sub 22} ordered structure, {beta}-Ni{sub 3}Si precipitate, {delta}-Ni{sub 2}Si precipitate and {gamma}-Ni{sub 5}Si{sub 2} precipitate) have been observed in previous investigation. Therefore, the overall phase transformation behavior of Cu-Ni-Si alloy appears to be very complex. And most previous studies on the phase transformation usually investigated the precipitation process at only one temperature or at most a few temperatures, which is far away to establish a time-temperature-transformation (TTT) diagram for Cu-Ni-Si alloy. > The phase transformation behavior of Cu-8.0Ni-1.8Si alloy has been studied systematically at wide temperature range in this paper. The results we have gained are that: after solution treatment, followed by different conditions of isothermal treatment, DO{sub 22} ordering, discontinuous precipitation and continuous precipitation were observed in the alloy; discontinuous precipitates of {beta}-Ni{sub 3}Si phase appeared when the alloy isothermal treated at 550 deg. C for short time, which had not been reported by the previous Cu-Ni-Si system alloy's researchers in their papers; two kinds of precipitates of {beta}-Ni{sub 3}Si and {delta}-Ni{sub 2}Si were determined by the TEM characterization; the orientation relationship between the two kinds of precipitates and Cu-matrix is that: (1 1 0){sub Cu}//(1 1 0){sub {beta}}//(211-bar){sub {delta}}, [112-bar]{sub Cu}//[11-bar 2]{sub {beta}}//[3 2 4]{sub {delta}}; during overaging treatment, Cu-matrix, {beta}-Ni{sub 3}Si, {delta}-Ni{sub 2}Si and {delta}'-Ni{sub 2}Si were distinguished in the samples and the orientation relationship between the precipitates and Cu-matrix can be expressed as that: (0 2 2){sub Cu}//(0 2 2){sub {beta}}//(1 0 0){sub {delta}}, (02-bar 2){sub Cu

Cap casting and enveloped casting techniques for Zr55Cu30Ni5Al10 glassy alloy rod with 32 mm in diameter

International Nuclear Information System (INIS)

Yokoyama, Yoshihiko; Inoue, Akihisa; Mund, Enrico; Schultz, Ludwig

2009-01-01

In order to produce centimetre-sized bulk glassy alloys (BMGs), various cast techniques have been developed. We succeed in the development of cap casting and enveloped casting technique to accomplish the fabrication of centimetre sized BMGs. The former has an advantage to increase cooling rate and the later has an advantage to joint another materials instead of welding. This paper presents the production of a glassy Zr 55 Cu 30 Ni 5 Al 10 alloy rod with a diameter of 32 mm and joined glassy Zr 55 Cu 30 Ni 5 Al 10 alloy parts with another materials for industrial applications.

Hydrogen absorption kinetics and structural properties of Mg85Ni10Ca5 and Mg90Ni10

International Nuclear Information System (INIS)

Aoki, Masakazu; Saito, Katsushi; Towata, Shin-ichi

2005-01-01

Mg 85 Ni 10 Ca 5 and Mg 90 Ni 10 were prepared by melting mixtures of the elements in mild steel crucibles and pouring them into copper molds. Hydrogen absorption kinetics and structural properties of the alloys were characterized by the volumetric method using a Sievert's apparatus, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The crystallite size of Mg in Mg 85 Ni 10 Ca 5 , which is evaluated by XRD peak broadening, is about 50% smaller than that in Mg 90 Ni 10 . In addition, the nanometer-scale structure composed of Mg, Mg 2 Ni, Mg 2 Ca was observed in Mg 85 Ni 10 Ca 5 . Mg 85 Ni 10 Ca 5 shows better hydrogen absorption kinetics than Mg 90 Ni 10 in the temperature range of room temperature to 573 K. The better absorption kinetics of Mg 85 Ni 10 Ca 5 is mainly attributed to the nanometer-scale structure

Martensitic transition, inverse magnetocaloric effect and shape memory characteristics in Mn{sub 48−x}Cu{sub x}Ni{sub 42}Sn{sub 10} Heusler alloys

Energy Technology Data Exchange (ETDEWEB)

Liu, Changqin [Department of Physics, Shanghai University, Shanghai 200444 (China); Li, Zhe [Reasearch center for magnetic materials and devices & Key Laboratory for Advanced Functional and Low Dimensional Materials of Yunnan Higher Education Institute, Qujing Normal University, Qujing 655011 (China); Zhang, Yuanlei [Department of Physics, Shanghai University, Shanghai 200444 (China); Reasearch center for magnetic materials and devices & Key Laboratory for Advanced Functional and Low Dimensional Materials of Yunnan Higher Education Institute, Qujing Normal University, Qujing 655011 (China); Liu, Yang; Sun, Junkun; Huang, Yinsheng; Kang, Baojuan [Department of Physics, Shanghai University, Shanghai 200444 (China); Xu, Kun [Reasearch center for magnetic materials and devices & Key Laboratory for Advanced Functional and Low Dimensional Materials of Yunnan Higher Education Institute, Qujing Normal University, Qujing 655011 (China); Deng, Dongmei [Department of Physics, Shanghai University, Shanghai 200444 (China); Jing, Chao, E-mail: cjing@staff.shu.edu.cn [Department of Physics, Shanghai University, Shanghai 200444 (China)

2017-03-01

In this paper, we have systematically prepared a serials of polycrystalline Mn{sub 48−x}Cu{sub x}Ni{sub 42}Sn{sub 10} alloys (x=0, 1, 3, 5, 6, 8, 10 and 12) and investigated the influence of the Cu doping on martensitic transition (MT) as well as magnetic properties. Experimental results indicate that the MT temperature and the martensite Curie temperature (T{sub c}{sup M}) shift to high temperature with increasing the substitution of Cu (from Mn rich alloy to Ni rich alloy), while the austenite Curie temperature (T{sub c}{sup A}) is almost unchanged. It was found that the structures undergo L2{sub 1} and 4O with the increasing of Cu concentration near room temperature. Therefore, the magnetostructural transition can be tuned by appropriate Cu doping in these alloys. Moreover, we mainly studied the multiple functional properties for inverse magnetocaloric effect and shape memory characteristics associated with the martensitic transition. A large positive isothermal entropy change of Mn{sub 48}Ni{sub 42}Sn{sub 10} was obtained, and the maximum transition entropy change achieves about 48 J/kg K as x=8. In addition, a considerable temperature-induced spontaneous strain with the value of 0.16% was obtained for Mn{sub 48}Ni{sub 42}Sn{sub 10} alloys.

Performance of ethanol electro-oxidation on Ni-Cu alloy nanowires through composition modulation.

Science.gov (United States)

Tian, Xi-Ke; Zhao, Xiao-Yu; Zhang, Li-de; Yang, Chao; Pi, Zhen-Bang; Zhang, Su-Xin

2008-05-28

To reduce the cost of the catalyst for direct ethanol fuel cells and improve its catalytic activity, highly ordered Ni-Cu alloy nanowire arrays have been fabricated successfully by differential pulse current electro-deposition into the pores of a porous anodic alumina membrane (AAMs). The energy dispersion spectrum, scanning and transmission electron microscopy were utilized to characterize the composition and morphology of the Ni-Cu alloy nanowire arrays. The results reveal that the nanowires in the array are uniform, well isolated and parallel to each other. The catalytic activity of the nanowire electrode arrays for ethanol oxidation was tested and the binary alloy nanowire array possesses good catalytic activity for the electro-oxidation of ethanol. The performance of ethanol electro-oxidation was controlled by varying the Cu content in the Ni-Cu alloy and the Ni-Cu alloy nanowire electrode shows much better stability than the pure Ni one.

Performance of ethanol electro-oxidation on Ni-Cu alloy nanowires through composition modulation

International Nuclear Information System (INIS)

Tian Xike; Zhao Xiaoyu; Yang Chao; Pi Zhenbang; Zhang Lide; Zhang Suxin

2008-01-01

To reduce the cost of the catalyst for direct ethanol fuel cells and improve its catalytic activity, highly ordered Ni-Cu alloy nanowire arrays have been fabricated successfully by differential pulse current electro-deposition into the pores of a porous anodic alumina membrane (AAMs). The energy dispersion spectrum, scanning and transmission electron microscopy were utilized to characterize the composition and morphology of the Ni-Cu alloy nanowire arrays. The results reveal that the nanowires in the array are uniform, well isolated and parallel to each other. The catalytic activity of the nanowire electrode arrays for ethanol oxidation was tested and the binary alloy nanowire array possesses good catalytic activity for the electro-oxidation of ethanol. The performance of ethanol electro-oxidation was controlled by varying the Cu content in the Ni-Cu alloy and the Ni-Cu alloy nanowire electrode shows much better stability than the pure Ni one

Minor-alloyed Cu-Ni-Si alloys with high hardness and electric conductivity designed by a cluster formula approach

Directory of Open Access Journals (Sweden)

Dongmei Li

2017-08-01

Full Text Available Cu-Ni-Si alloys are widely used due to their good electrical conductivities in combination with high strength and hardness. In the present work, minor-alloying with M = (Cr, Fe, Mo, Zr was conducted for the objective of further improving their hardness while maintaining their conductivity level. A cluster-plus-glue-atom model was introduced to design the compositions of M-alloyed Cu-Ni-Si alloys, in which an ideal composition formula [(Ni,Si,M-Cu12]Cu3 (molar proportion was proposed. To guarantee the complete precipitation of solute elements in fine δ-Ni2Si precipitates, the atomic ratio of (Ni,M/Si was set as 2/1. Thus the designed alloy series of Cu93.75(Ni/Zr3.75Si2.08(Cr/Fe/Mo0.42 (at% were arc-melted into ingots under argon atmosphere, and solid-solutioned at 950 °C for 1 h plus water quenching and then aged at 450 °C for different hours. The experimental results showed that these designed alloys exhibit high hardness (HV > 1.7 GPa and good electrical conductivities (≥ 35% IACS. Specifically, the quinary Cu93.75Ni3.54Si2.08(Cr/Fe0.42Zr0.21 alloys (Cu-3.32Ni-0.93Si-0.37(Cr/Fe−0.30Zr wt% possess both a high hardness with HV = 2.5–2.7 GPa, comparable to the high-strength KLFA85 alloy (Cu-3.2Ni-0.7Si-1.1Zn wt%, HV = 2.548 GPa, and a good electrical conductivity (35–36% IACS.

Copper and CuNi alloys substrates for HTS coated conductor applications protected from oxidation

Energy Technology Data Exchange (ETDEWEB)

Segarra, M; Diaz, J; Xuriguera, H; Chimenos, J M; Espiell, F [Dept. of Chemical Engineering and Metallurgy, Univ. of Barcelona, Barcelona (Spain); Miralles, L [Lab. d' Investigacio en Formacions Geologiques. Dept. of Petrology, Geochemistry and Geological Prospecting, Univ. of Barcelona, Barcelona (Spain); Pinol, S [Inst. de Ciencia de Materials de Barcelona, Bellaterra (Spain)

2003-07-01

Copper is an interesting substrate for HTS coated conductors for its low cost compared to other metallic substrates, and for its low resistivity. Nevertheless, mechanical properties and resistance to oxidation should be improved in order to use it as substrate for YBCO deposition by non-vacuum techniques. Therefore, different cube textured CuNi tapes were prepared by RABIT as possible substrates for deposition of high critical current density YBCO films. Under the optimised conditions of deformation and annealing, all the studied CuNi alloys (2%, 5%, and 10% Ni) presented (100) left angle 001 right angle cube texture which is compatible for YBCO deposition. Textured CuNi alloys present higher tensile strength than pure copper. Oxidation resistance of CuNi tapes under different oxygen atmospheres was also studied by thermogravimetric analysis and compared to pure copper tapes. Although the presence of nickel improves mechanical properties of annealed copper, it does not improve its oxidation resistance. However, when a chromium buffer layer is electrodeposited on the tape, oxygen diffusion is slowed down. Chromium is, therefore, useful for protecting copper and CuNi alloys from oxidation although its recrystallisation texture, (110), is not suitable for coated conductors. (orig.)

Studies of the development and characterization of the Cu-Ni-Pt and Cu-Ni-Sn alloys for electro-electronic uses; Estudos do desenvolvimento e caracterizacao das ligas Cu-Ni-Pt e Cu-Ni-Sn para fins eletro-eletronicos

Energy Technology Data Exchange (ETDEWEB)

Silva, Luis Carlos Elias da

2006-07-01

The Cu and its alloys have different applications in the owed modern society the excellent electric properties, thermal conductivity, resistance to the corrosion and other properties. These applications can be in valves, pipes, pots for absorption of solar energy, radiators for automobiles, current driver, electronic driver, thermostats elements and structural parts of nuclear reactors, as, for example, reels for field toroidal for a reactor of nuclear coalition. The alloys used in nuclear reactors, we can highlight Cu-Be, Cu-Sn and Cu-Pt. Ni and Co frequently are added to the Cu alloys so that the solubility is moved for temperatures more elevated with relationship to the binary systems of Cu-Sn and Cu-Pt. The addition of Ni-Pt or Ni-Sn to the Cu in the same or inferior percentages to 1,5% plus thermomechanical treatments changes the properties of the copper. We studied the electric conductivity and hardness Vickers of the Cu-Ni-Pt and Cu-Ni-Sn and compared with the electrolytic Cu. In the proposed flowcharts, breaking of the obtaining of the ingot, we proceeded with thermo mechanical treatments. (author)

Effect of solute Cu on ductile-to-brittle behavior of martensitic Fe-8% Ni alloy

International Nuclear Information System (INIS)

Junaidi Syarif; Tsuchiyama, Toshihiro; Takaki, Setsuo

2007-01-01

Effect of solute Cu on the ductile-to-brittle (DBT) behaviour of martensitic Fe-8mass%Ni alloy is investigated to understand the effect of solute Cu on mechanical properties of martensitic steel. The DBT behaviours of the Fe-8mass%Ni and the Fe-8mass%Ni-1mass%Cu alloys are almost the same. It is thought to be due to disappearance of the solid solution softening in the martensitic Fe-8mass%Ni-Cu alloys. The solute Cu gives small influence on temperature and strain rate dependences of yield stress and suppressing the twin deformation at lower temperature in the martensitic Fe-8mass%Ni alloy. Therefore, the DBT temperature of the martensitic Fe-8mass%Ni-Cu alloy was not shifted to lower side. (author)

A diffuse neutron scattering study of clustering kinetics in Cu-Ni alloys

International Nuclear Information System (INIS)

Vrijen, J.; Radelaar, S.; Schwahn, D.

1977-01-01

Diffuse scattering of thermal neutrons was used to investigate the kinetics of clustering in Cu-Ni alloys. In order to optimize the experimental conditions the isotopes 65 Cu and 62 Ni were alloyed. The time evolution of the diffuse scattered intensity at 400 0 C has been measured for eight Cu-Ni alloys, varying in composition between 30 and 80 at. pour cent Ni. The relaxation of the so called null matrix, containing 56.5 at. pour cent Ni has also been investigated at 320, 340, 425 and 450 0 C. Using Cook's model from all these measurements information has been deduced about diffusion at low temperatures and about thermodynamic properties of the Cu-Ni system. It turns out that Cook's model is not sufficiently detailed for an accurate description of the initial stages of these relaxations

Hydrogen storage properties of LaMgNi3.6M0.4 (M = Ni, Co, Mn, Cu, Al) alloys

International Nuclear Information System (INIS)

Yang, Tai; Zhai, Tingting; Yuan, Zeming; Bu, Wengang; Xu, Sheng; Zhang, Yanghuan

2014-01-01

Highlights: • La–Mg–Ni system AB 2 -type alloys were prepared by induction melting. • Structures and lattice parameters were analysed by XRD. • Hydrogen absorption/desorption performances were studied. • Mechanisms of hydrogen absorption capacity fading were investigated. - Abstract: LaMgNi 3.6 M 0.4 (M = Ni, Co, Mn, Cu, Al) alloys were prepared through induction melting process. The phase compositions and crystal structures were characterised via X-ray diffraction (XRD). The hydrogen storage properties, including activation performance, hydrogen absorption capacity, cycle stability, alloy particle pulverisation and plateau pressure, were systemically investigated. Results show that Ni, Co, Mn and Cu substitution alloys exhibit multiphase structures comprising the main phase LaMgNi 4 and the secondary phase LaNi 5 . However, the secondary phase of the Al substitution alloy changes into LaAlNi 4 . The lattice parameters and cell volumes of the LaMgNi 4 phase follow the order Ni < Co < Al < Cu < Mn. Activation is simplified through partial substitution of Ni with Al, Cu and Co. The hydrogen absorption capacities of all of the alloys are approximately 1.7 wt.% at the first activation process; however, they rapidly decrease with increasing cycle number. In addition, the stabilities of hydriding and dehydriding cycles decrease in the order Al > Co > Ni > Cu > Mn. Hydriding processes result in numerous cracks and amorphisation of the LaMgNi 4 phase in the alloys. The p–c isotherms were determined by a Sieverts-type apparatus. Two plateaus were observed for the Ni, Co and Al substitution alloys, whereas only one plateau was found for Mn and Cu. This result was caused by the amorphisation of the LaMgNi 4 phase during the hydriding cycles. Reversible absorption and desorption of hydrogen are difficult to achieve. Substitutions of Ni with Co, Mn, Cu and Al significantly influence the reduction of hysteresis between hydriding and dehydriding

Wetting Behavior of Ternary Au-Ge-X (X = Sb, Sn) Alloys on Cu and Ni

Science.gov (United States)

Jin, S.; Valenza, F.; Novakovic, R.; Leinenbach, C.

2013-06-01

Au-Ge-based alloys are potential substitutes for Pb-rich solders currently used for high-temperature applications. In the present work, the wetting behavior of two Au-Ge-X (X = Sb, Sn) ternary alloys, i.e., Au-15Ge-17Sb and Au-13.7 Ge-15.3Sn (at.%), in contact with Cu and Ni substrates has been investigated. Au-13.7Ge-15.3Sn alloy showed complete wetting on both Cu and Ni substrates. Total spreading of Au-15Ge-17Sb alloy on Cu was also observed, while the final contact angle of this alloy on Ni was about 29°. Pronounced dissolution of Cu substrates into the solder alloys investigated was detected, while the formation of Ni-Ge intermetallic compounds at the interface of both solder/Ni systems suppressed the dissolution of Ni into the solder.

Thermal stability and primary phase of Al-Ni(Cu)-La amorphous alloys

International Nuclear Information System (INIS)

Huang Zhenghua; Li Jinfu; Rao Qunli; Zhou Youhe

2008-01-01

Thermal stability and primary phase of Al 85+x Ni 9-x La 6 (x = 0-6) and Al 85 Ni 9-x Cu x La 6 (x = 0-9) amorphous alloys were investigated by X-ray diffraction and differential scanning calorimeter. It is revealed that replacing Ni in the Al 85 Ni 9 La 6 alloy by Cu decreases the thermal stability and makes the primary phase change from intermetallic compounds to single fcc-Al as the Cu content reaches and exceeds 4 at.%. When the Ni and La contents are fixed, replacing Al by Cu increases the thermal stability but also promotes the precipitation of single fcc-Al as the primary phase

Preparation of Zr50Al15− xNi10Cu25Yx amorphous powders by ...

Indian Academy of Sciences (India)

The as-milled powders were characterized by X-ray diffraction and transmission electron microscopy. The results show that partial substitution of Al by Y can improve the glass-forming ability of Zr50Al15Ni10Cu25 alloy. Thermodynamic calculation of equivalent free energy shows that Zr50Al13.8Ni10Cu25Y1.2 alloy has the ...

Hydrogen storage properties of LaMgNi{sub 3.6}M{sub 0.4} (M = Ni, Co, Mn, Cu, Al) alloys

Energy Technology Data Exchange (ETDEWEB)

Yang, Tai [Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081 (China); Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-Metal Resources, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Zhai, Tingting; Yuan, Zeming; Bu, Wengang [Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081 (China); Xu, Sheng [Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-Metal Resources, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Zhang, Yanghuan, E-mail: zhangyh59@sina.com [Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081 (China); Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-Metal Resources, Inner Mongolia University of Science and Technology, Baotou 014010 (China)

2014-12-25

Highlights: • La–Mg–Ni system AB{sub 2}-type alloys were prepared by induction melting. • Structures and lattice parameters were analysed by XRD. • Hydrogen absorption/desorption performances were studied. • Mechanisms of hydrogen absorption capacity fading were investigated. - Abstract: LaMgNi{sub 3.6}M{sub 0.4} (M = Ni, Co, Mn, Cu, Al) alloys were prepared through induction melting process. The phase compositions and crystal structures were characterised via X-ray diffraction (XRD). The hydrogen storage properties, including activation performance, hydrogen absorption capacity, cycle stability, alloy particle pulverisation and plateau pressure, were systemically investigated. Results show that Ni, Co, Mn and Cu substitution alloys exhibit multiphase structures comprising the main phase LaMgNi{sub 4} and the secondary phase LaNi{sub 5}. However, the secondary phase of the Al substitution alloy changes into LaAlNi{sub 4}. The lattice parameters and cell volumes of the LaMgNi{sub 4} phase follow the order Ni < Co < Al < Cu < Mn. Activation is simplified through partial substitution of Ni with Al, Cu and Co. The hydrogen absorption capacities of all of the alloys are approximately 1.7 wt.% at the first activation process; however, they rapidly decrease with increasing cycle number. In addition, the stabilities of hydriding and dehydriding cycles decrease in the order Al > Co > Ni > Cu > Mn. Hydriding processes result in numerous cracks and amorphisation of the LaMgNi{sub 4} phase in the alloys. The p–c isotherms were determined by a Sieverts-type apparatus. Two plateaus were observed for the Ni, Co and Al substitution alloys, whereas only one plateau was found for Mn and Cu. This result was caused by the amorphisation of the LaMgNi{sub 4} phase during the hydriding cycles. Reversible absorption and desorption of hydrogen are difficult to achieve. Substitutions of Ni with Co, Mn, Cu and Al significantly influence the reduction of hysteresis between

Influences of hydrostatic pressure during casting and Pd content on as-cast phase in Zr-Al-Ni-Cu-Pd bulk alloys

International Nuclear Information System (INIS)

Kato, Hidemi; Inoue, Akihisa; Saida, Junji

2004-01-01

The influences of sample diameter (D), Pd content (x), and hydrostatic pressure (P) in a chamber during casting on the structure of as cast Zr 65 Al 7.5 Ni 10 Cu 17.5-x Pd x (x=10,17.5 at.%) bulk alloys were investigated. Zr 65 Al 7.5 Ni 10 Cu 7.5 Pd 10 and Zr 65 Al 7.5 Ni 10 Pd 17.5 alloys (D=3 mm) cast in a vacuum chamber (P∼4.0x10 -3 Pa) were mainly of the tetragonal-Zr 2 Ni equilibrium phase and nanosize icosahedral primary phase, respectively, while the same alloys cast in inert argon gas at atmospheric pressure (P∼0.1 MPa) were of the single glassy phase. Due to the higher cooling rate obtained by decreasing the sample diameter (D=2 mm) even in the vacuum chamber, the Zr 65 Al 7.5 Ni 10 Pd 17.5 alloy was still of the icosahedral phase, while the Zr 65 Al 7.5 Ni 10 Cu 7.5 Pd 10 alloy froze into a single glassy phase. These results indicate that the temperature- and time- transformation curves for the icosahedral and subsequent equilibrium phase formations in the alloy system shifts to a shorter time side with decreasing P, and the pressure sensitivity of the icosahedral phase formation increases with x

Phase formation in as-solidified and heat-treated Al-Si-Cu-Mg-Ni alloys: Thermodynamic assessment and experimental investigation for alloy design

Energy Technology Data Exchange (ETDEWEB)

Farkoosh, A.R., E-mail: amir.rezaeifarkoosh@mail.mcgill.ca [Department of Mining and Materials Engineering, McGill University, 3610 University, Aluminum Research Center - REGAL, Montreal, Quebec, Canada H3A 2B2 (Canada); Javidani, M. [Laval University, Department of Mining, Metallurgy and Materials Engineering, Aluminum Research Center - REGAL, 1065 Ave de la Medecine, Quebec, Canada G1V 0A6 (Canada); Hoseini, M. [Department of Mining and Materials Engineering, McGill University, 3610 University, Aluminum Research Center - REGAL, Montreal, Quebec, Canada H3A 2B2 (Canada); Larouche, D. [Laval University, Department of Mining, Metallurgy and Materials Engineering, Aluminum Research Center - REGAL, 1065 Ave de la Medecine, Quebec, Canada G1V 0A6 (Canada); Pekguleryuz, M. [Department of Mining and Materials Engineering, McGill University, 3610 University, Aluminum Research Center - REGAL, Montreal, Quebec, Canada H3A 2B2 (Canada)

2013-02-25

Highlights: Black-Right-Pointing-Pointer Phase formation in Al-Si-Ni-Cu-Mg-Fe system have been investigated. Black-Right-Pointing-Pointer T-Al{sub 9}FeNi, {gamma}-Al{sub 7}Cu{sub 4}Ni, {delta}-Al{sub 3}CuNi and {epsilon}-Al{sub 3}Ni are formed at different Ni levels. Black-Right-Pointing-Pointer Thermally stable Ni-bearing precipitates improved the overaged hardness. Black-Right-Pointing-Pointer It was found that Ni:Cu and Ni:Fe ratios control the precipitation. Black-Right-Pointing-Pointer {delta}-Al{sub 3}CuNi phase has more contribution to strength compare to other precipitates. - Abstract: Thermodynamic simulations based on the CALPHAD method have been carried out to assess the phase formation in Al-7Si-(0-1)Ni-0.5Cu-0.35Mg alloys (in wt.%) under equilibrium and non-equilibrium (Scheil cooling) conditions. Calculations showed that the T-Al{sub 9}FeNi, {gamma}-Al{sub 7}Cu{sub 4}Ni, {delta}-Al{sub 3}CuNi and {epsilon}-Al{sub 3}Ni phases are formed at different Ni levels. By analyzing the calculated isothermal sections of the phase diagrams it was revealed that the Ni:Cu and Ni:Fe ratios control precipitation in this alloy system. In order to verify the simulation results, microstructural investigations in as-cast, solution treated and aged conditions were carried out using electron probe microanalysis (EPMA), scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Furthermore, cooling curve analysis (CCA) was also performed to determine the freezing range of the new alloys and porosity formation during solidification. Hardness measurements of the overaged samples showed that in this alloy system the {delta}-Al{sub 3}CuNi phase has a greater influence on the overall strength of the alloys compared to the other Ni-bearing precipitates.

Fabrication and Characterization of novel W80Ni10Nb10 alloy produced by mechanical alloying

Science.gov (United States)

Saxena, R.; Patra, A.; Karak, S. K.; Pattanaik, A.; Mishra, S. C.

2016-02-01

Nanostructured tungsten (W) based alloy with nominal composition of W80Ni10Nb10 (in wt. %) was synthesized by mechanical alloying of elemental powders of tungsten (W), nickel (Ni), niobium (Nb) in a high energy planetary ball-mill for 20 h using chrome steel as grinding media and toluene as process control agent followed by compaction at 500 MPa pressure for 5 mins and sintering at 1500°C for 2 h in Ar atmosphere. The phase evolution and the microstructure of the milled powder and consolidated product were investigated by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The crystallite size of W in W80Ni10Nb10 powder was reduced from 100 μm at 0 h to 45.6 nm at 10 h and 34.1 nm at 20 h of milling whereas lattice strain increases to 35% at 20 h of milling. The dislocation density shows sharp increase up to 5 h of milling and the rate of increase drops beyond 5 to 20 h of milling. The lattice parameter of tungsten in W80Ni10Nb10 expanded upto 0.04% at 10 h of milling and contracted upto 0.02% at 20 h of milling. The SEM micrograph revealed the presence of spherical and elongated particles in W80Ni10Nb10 powders at 20 h of milling. The particle size decreases from 100 μm to 2 μm with an increase in the milling time from 0 to 20 hours. The crystallite size of W in milled W80Ni10Nb10 alloy as evident from bright field TEM image was in well agreement with the measured crystallite size from XRD. Structure of W in 20 h milled W80Ni10Nb10 alloy was identified by indexing of selected area diffraction (SAD) pattern. Formation of NbNi intermetallic was evident from XRD pattern and SEM micrograph of sintered alloy. Maximum sinterability of 90.8% was achieved in 20 h milled sintered alloy. Hardness and wear study was also conducted to investigate the mechanical behaviour of the sintered product. Hardness of W80Ni10Nb10 alloy reduces with increasing load whereas wear rate increases with increasing load. The evaluated

Fusion and characterization of an alloy Cu-Zn-Al-Ni of nuclear interest

International Nuclear Information System (INIS)

Santana M, J.S.

2003-01-01

The present work is the result of the study of a non ferrous quatenary alloy of Cu-Zn-Al-Ni (Foundry 3), it was chosen of a series of alloys to obtain so much information of its microstructural properties like mechanical, evaluating them and comparing them with the previously obtained ternary alloys of Cu-AI-Ni (Foundry 1) and Cu-Zn-AI (Foundry 2) identified as alloys of memory effect and superalloys. These were carried out starting from the foundry of their pure elements of Cu, Zn, Al, Ni. When physically having the ingot of each alloy, different techniques were used for their characterization. The used techniques were through the metallographic analysis, by scanning electron microscopy (SEM), X-ray dispersive energy spectroscopy (EDS), X-ray diffraction (XRD), mechanical essays and Rockwell hardness. The non ferrous quaternary alloy Cu-Zn-AI-Ni by means of the metallographic analysis didn't show significant differences in their three sections (superficial, longitudinal and transverse) since result an homogeneous alloy at the same that the both ternaries. The grain size of the quaternary alloy is the finest while the ternary alloy of Cu-AI-Ni is the one that obtained the biggest grain size. Through MEB together with the analysis by EDS and the mapping of the elements that constitute each alloy, show that the three foundries were alloyed, moreover the presence of aggregates was also observed in the Foundries 2 and 3. These results by means of the analysis of XRD corroborate that these alloys have more of two elements. Relating the microstructural properties with those mechanical show us that as minor was the grain size, better they were his mechanical properties, in this case that of the quaternary alloy. With regard to the test of Rockwell hardness the Foundry 1 were the softest with the temper treatment, while that the Foundries 2 and 3 were the hardest with this same treatment, being still harder the Foundry 2 but with very little difference, for what great

Effect of Cu Alloying on S Poisoning of Ni Surfaces and Nanoparticle Morphologies Using Ab-Initio Thermodynamics Calculations.

Science.gov (United States)

Kim, Ji-Su; Kim, Byung-Kook; Kim, Yeong-Cheol

2015-10-01

We investigated the effect of Cu alloying on S poisoning of Ni surfaces and nanoparticle morphologies using ab-initio thermodynamics calculations. Based on the Cu segregation energy and the S adsorption energy, the surface energy and nanoparticle morphology of pure Ni, pure Cu, and NiCu alloys were evaluated as functions of the chemical potential of S and the surface orientations of (100), (110), and (111). The constructed nanoparticle morphology was varied as a function of chemical potential of S. We find that the Cu added to Ni for NiCu alloys is strongly segregated into the top surface, and increases the S tolerance of the NiCu nanoparticles.

Correlation of plastic deformation induced intermittent electromagnetic radiation characteristics with mechanical properties of Cu-Ni alloys

International Nuclear Information System (INIS)

Singh, Ranjana; Lal, Shree P.; Misra, Ashok

2015-01-01

This paper presents experimental results on intermittent electromagnetic radiation during plastic deformation of Cu-Ni alloys under tension and compression modes of deformation. On the basis of the nature of electromagnetic radiation signals, oscillatory or exponential, results show that the compression increases the viscous coefficient of Cu-Ni alloys during plastic deformation. Increasing the percentage of solute atoms in Cu-Ni alloys makes electromagnetic radiation strength higher under tension. The electromagnetic radiation emission occurs at smaller strains under compression showing early onset of plastic deformation. This is attributed to the role of high core region tensile residual stresses in the rolled Cu-Ni alloy specimens in accordance with the Bauschinger effect. The distance between the apexes of the dead metal cones during compression plays a significant role in electromagnetic radiation parameters. The dissociation of edge dislocations into partials and increase in internal stresses with increase in solute percentage in Cu-Ni alloys under compression considerably influences the electromagnetic radiation frequency.

Anodic dissolution and corrosion of alloy Cu30Ni in chloride solutions

International Nuclear Information System (INIS)

Zolotarev, E.I.

1989-01-01

The anodic and corrosion behavior of alloy Cu30Ni is studied in a solution of 3 N NaCl + 0.01 N HCl by a radiometric method using gamma isotopes of 58 Co (as a marker for Ni) and 64 Cu in combination with electrochemical measurements. It was established that under stationary conditions there was uniform dissolution of the alloy both during free corrosion and anodic polarization. The authors obtained partial anodic dissolution curves for the components of the alloy. It was shown that the dissolution kinetics differed from the mechanisms controlling dissolution of the corresponding pure metals. During corrosion of the alloy in an oxygen atmosphere a back precipitation of copper on the surface of the alloy was not observed. The characteristics observed in the corrosion-electrochemical behavior of the alloy in concentrated chloride solutions can be explained by the presence of Ni on the surface of the dissolving alloy

The response of macrophages to a Cu-Al-Ni shape memory alloy.

Science.gov (United States)

Colić, Miodrag; Tomić, Sergej; Rudolf, Rebeka; Anzel, Ivan; Lojen, Gorazd

2010-09-01

Cu-Al-Ni shape memory alloys (SMAs) have been investigated as materials for medical devices, but little is known about their biocompatibility. The aim of this work was to study the response of rat peritoneal macrophages (PMØ) to a Cu-Al-Ni SMA in vitro, by measuring the functional activity of mitochondria, necrosis, apoptosis, and production of proinflammatory cytokines. Rapidly solidified (RS) thin ribbons were used for the tests. The control alloy was a permanent mold casting of the same composition, but without the shape memory effect. Our results showed that the control alloy was severely cytotoxic, whereas RS ribbons induced neither necrosis nor apoptosis of PMØ. These findings correlated with the data that RS ribbons are significantly more resistant to corrosion compared to the control alloy, as judged by the lesser release of Cu and Ni in the conditioning medium. However, the ribbons generated intracellular reactive oxygen species and upregulated the production of IL-6 by PMØ. These effects were almost completely abolished by conditioning the RS ribbons for 5 weeks. In conclusion, RS significantly improves the corrosion stability and biocompatibility of Cu-Al-Ni SMA. The biocompatibility of this functional material could be additionally enhanced by conditioning the ribbons in cell culture medium.

Creep behaviour of a casting titanium carbide reinforced AlSi12CuNiMg piston alloy at elevated temperatures; Hochtemperaturkriechverhalten der schmelzmetallurgisch hergestellten dispersionsverstaerkten Kolbenlegierung AlSi12CuNiMg

Energy Technology Data Exchange (ETDEWEB)

Michel, S.; Scholz, A. [Zentrum fuer Konstruktionswerkstoffe, TU Darmstadt (Germany); Tonn, B. [Institut fuer Metallurgie, TU Clausthal (Germany); Zak, H.

2012-03-15

This paper deals with the creep behaviour of the titanium carbide reinforced AlSi12CuNiMg piston alloy at 350 C and its comparison to the conventional AlSi12Cu4Ni2MgTiZr piston alloy. With only 0,02 vol-% TiC reinforcement the creep strength and creep rupture strength of the AlSi12CuNiMg piston alloy are significantly improved and reach the level of the expensive AlSi12Cu4Ni2MgTiZr alloy. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Effect of iron content on the structure and mechanical properties of Al25Ti25Ni25Cu25 and (AlTi)60-xNi20Cu20Fex (x=15, 20) high-entropy alloys

International Nuclear Information System (INIS)

Fazakas, É.; Zadorozhnyy, V.; Louzguine-Luzgin, D.V.

2015-01-01

Highlights: • Three new refractory alloys namely: Al 25 Ti 25 Ni 25 Cu 25 , Al 22.5 Ti 22.5 Ni 20 Cu 20 Fe 15 and Al 20 Ti 20 Ni 20 Cu 20 Fe 20 , were produced by induction-melting and casting. • This kind of alloys exhibits high resistance to annealing softening. • Most the alloys in the annealed state possess even higher Vickers microhardness than the as-cast alloys. • The Al 22.5 Ti 22.5 Ni 20 Cu 20 Fe 15 and Al 20 Ti 20 Ni 20 Cu 20 Fe 20 alloys annealed at 973 K show the highest compressive stress and ductility values. - Abstract: In this work, we investigated the microstructure and mechanical properties of Al 25 Ti 25 Ni 25 C u25 Al 22.5 Ti 22.5 Ni 20 Cu 20 Fe 15 and Al 20 Ti 20 Ni 20 Cu 20 Fe 20 high entropy alloys, produced by arc melting and casting in an inert atmosphere. The structure of these alloys was studied by X-ray diffractometry and scanning electron microscopy. The as-cast alloys were heat treated at 773, 973 and 1173 K for 1800 s to investigate the effects of aging on the plasticity, hardness and elastic properties. Compared to the conventional high-entropy alloys the Al 25 Ti 25 Ni 25 Cu 25 , Al 22.5 Ti 22.5 Ni 20 Cu 20 Fe 15 and Al 20 Ti 20 Ni 20 Cu 20 Fe 20 alloys are relatively hard and ductile. Being heat treated at 973 K the Al 22.5 Ti 22.5 Ni 20 Cu 20 Fe 15 alloy shows considerably high strength and relatively homogeneous deformation under compression. The plasticity, hardness and elastic properties of the studied alloys depend on the fraction and intrinsic properties of the constituent phases. Significant hardening effect by the annealing is found.

Kinetic study of the annealing reactions in Cu-Ni-Fe alloys

International Nuclear Information System (INIS)

Donoso, E.

2014-01-01

The thermal aging of a Cu-45Ni-4Fe, Cu-34Ni-11Fe and Cu-33Ni-22Fe alloys tempered from 1173 K have been studied from Differential Scanning Calorimetry (DSC) and microhardness measurements. The analysis of DSC curves, from room temperature to 950 K, shows the presence of one exothermic reaction associated to the formation of FeNi 3 phase nucleating from a modulate structure, and one endothermic peak attributed to dissolution of this phase. Kinetic parameters were obtained using the usual Avrami-Erofeev equation, modified Kissinger method and integrated kinetic functions. Microhardness measurements confirmed the formation and dissolution of the FeNi 3 phase. (Author)

Effects of Ti addition and heat treatments on mechanical and electrical properties of Cu-Ni-Si alloys

Science.gov (United States)

Kim, Hyung Giun; Lee, Taeg Woo; Kim, Sang Min; Han, Seung Zeon; Euh, Kwangjun; Kim, Won Yong; Lim, Sung Hwan

2013-01-01

The mechanical and electrical properties of Cu-5.98Ni-1.43Si and Cu-5.98Ni-1.29Si-0.24Ti alloys under heat treatment at 400 and 500 °C after hot- and cold-rolling were investigated, and a microstructural analysis using transmission electron microscopy was performed. Cu-5.98Ni-1.29Si-0.24Ti alloy displayed the combined Vickers hardness/electrical conductivity value of 315.9 Hv/57.1%IACS. This was attributed to a decrease of the solution solubility of Ni and Si in the Cu matrix by the formation of smaller and denser δ-Ni2Si precipitates. Meanwhile, the alloyed Ti was detected in the coarse Ni-Si-Ti phase particles, along with other large Ni-Si phase particles, in Cu-5.98Ni-1.29Si-0.24Ti.

Stability of an amorphous alloy of the Mm-Al-Ni-Cu system

Directory of Open Access Journals (Sweden)

Carlos Triveño Rios

2012-10-01

Full Text Available An investigation was made of the stability of melt-spun ribbons of Mm55Al25Ni10Cu10 (Mm = Mischmetal amorphous alloy. The structural transformations that occurred during heating were studied using a combination of X-ray diffraction (XRD and differential scanning calorimetry (DSC. Crystallization took place through a multi-stage process. The first stage of transformation corresponded to the formation of a metastable phase followed by cfc-Al precipitation, while in the second stage, exothermic transformations led to the formation of complex and unidentified Mm(Cu, Ni and MmAl(Cu, Ni phases. The transformation curves recorded from isothermal treatments at 226 °C and 232 °C indicated that crystallization occurred through nucleation and growth, with diffusion-controlled growth occurring in the first crystallization stage. The supercooled liquid region, ∆Tx, at 40 K/min was ~80 K. This value was obtained by the substitution of Mm (=Ce + La + Nd + Pr for La or Ce, saving chemical element-related costs.

Bulk glass formation and crystallization in Zr54.5Cu20Al10Ni8Ti7.5 alloy

International Nuclear Information System (INIS)

Neogy, S.; Tewari, R.; Srivastava, D.; Dey, G.K.; Kumar, V.; Ranganathan, S.

2006-01-01

The present work was aimed at fabrication, characterization and crystallization of Zr 54.5 Cu 20 Al 10 Ni 8 Ti 7.5 bulk metallic glass. The glass forming alloy was made by arc melting and then subjected to copper mold casting into 3 mm diameter bulk glass rods. The as-cast microstructure was characterized by optical microscopy and transmission electron microscopy (TEM)

Designing a New Ni-Mn-Sn Ferromagnetic Shape Memory Alloy with Excellent Performance by Cu Addition

Directory of Open Access Journals (Sweden)

Kun Zhang

2018-02-01

Full Text Available Both magnetic-field-induced reverse martensitic transformation (MFIRMT and a high working temperature are crucial for the application of Ni-Mn-Sn magnetic shape memory alloys. Here, by first-principles calculations, we demonstrate that the substitution of Cu for Sn is effective not only in enhancing the MFIRMT but also in increasing martensitic transformation, which is advantageous for its application. Large magnetization difference (ΔM in Ni-Mn-Sn alloy is achieved by Cu doping, which arises from the enhancement of magnetization of austenite due to the change of Mn-Mn interaction from anti-ferromagnetism to ferromagnetism. This directly leads to the enhancement of MFIRMT. Meanwhile, the martensitic transformation shifts to higher temperature, owing to the energy difference between the austenite L21 structure and the tetragonal martensite L10 structure increases by Cu doping. The results provide the theoretical data and the direction for developing a high temperature magnetic-field-induced shape memory alloy with large ΔM in the Ni-Mn-Sn Heusler alloy system.

A new Ti-Zr-Hf-Cu-Ni-Si-Sn bulk amorphous alloy with high glass-forming ability

International Nuclear Information System (INIS)

Huang, Y.J.; Shen, J.; Sun, J.F.; Yu, X.B.

2007-01-01

The effect of Sn substitution for Cu on the glass-forming ability was investigated in Ti 41.5 Zr 2.5 Hf 5 Cu 42.5-x Ni 7.5 Si 1 Sn x (x = 0, 1, 3, 5, 7) alloys by using differential scanning calorimetry (DSC) and X-ray diffractometry. The alloy containing 5% Sn shows the highest glass-forming ability (GFA) among the Ti-Zr-Hf-Cu-Ni-Si-Sn system. Fully amorphous rod sample with diameters up to 6 mm could be successfully fabricated by the copper mold casting Ti 41.5 Zr 2.5 Hf 5 Cu 37.5 Ni 7.5 Si 1 Sn 5 alloy. The activation energies for glass transition and crystallization for Ti 41.5 Zr 2.5 Hf 5 Cu 37.5 Ni 7.5 Si 1 Sn 5 amorphous alloy are both larger than those values for the Sn-free alloy. The enhancement in GFA and thermal stability after the partial replacement of Cu by Sn may be contributed to the strong atomic bonding nature between Ti and Sn and the increasing of atomic packing density. The amorphous Ti 41.5 Zr 2.5 Hf 5 Cu 37.5 Ni 7.5 Si 1 Sn 5 alloy also possesses superior mechanical properties

On the Path to Optimizing the Al-Co-Cr-Cu-Fe-Ni-Ti High Entropy Alloy Family for High Temperature Applications

Directory of Open Access Journals (Sweden)

Anna M. Manzoni

2016-03-01

Full Text Available The most commonly investigated high entropy alloy, AlCoCrCuFeNi, has been chosen for optimization of its microstructural and mechanical properties by means of compositional changes and heat treatments. Among the different available optimization paths, the decrease of segregating element Cu, the increase of oxidation protective elements Al and Cr and the approach towards a γ-γ′ microstructure like in Ni-based superalloys have been probed and compared. Microscopical observations have been made for every optimization step. Vickers microhardness measurements and/or tensile/compression test have been carried out when the alloy was appropriate. Five derived alloys AlCoCrFeNi, Al23Co15Cr23Cu8Fe15Ni16, Al8Co17Cr17Cu8Fe17Ni33, Al8Co17Cr14Cu8Fe17Ni34.8Mo0.1Ti1W0.1 and Al10Co25Cr8Fe15Ni36Ti6 (all at.% have been compared to the original AlCoCrCuFeNi and the most promising one has been selected for further investigation.

Fusion and characterization of an alloy Cu-Zn-Al-Ni of nuclear interest; Fusion y caracterizacion de una aleacion Cu-Zn-Al-Ni de interes nuclear

Energy Technology Data Exchange (ETDEWEB)

Santana M, J.S

2003-07-01

The present work is the result of the study of a non ferrous quatenary alloy of Cu-Zn-Al-Ni (Foundry 3), it was chosen of a series of alloys to obtain so much information of its microstructural properties like mechanical, evaluating them and comparing them with the previously obtained ternary alloys of Cu-AI-Ni (Foundry 1) and Cu-Zn-AI (Foundry 2) identified as alloys of memory effect and superalloys. These were carried out starting from the foundry of their pure elements of Cu, Zn, Al, Ni. When physically having the ingot of each alloy, different techniques were used for their characterization. The used techniques were through the metallographic analysis, by scanning electron microscopy (SEM), X-ray dispersive energy spectroscopy (EDS), X-ray diffraction (XRD), mechanical essays and Rockwell hardness. The non ferrous quaternary alloy Cu-Zn-AI-Ni by means of the metallographic analysis didn't show significant differences in their three sections (superficial, longitudinal and transverse) since result an homogeneous alloy at the same that the both ternaries. The grain size of the quaternary alloy is the finest while the ternary alloy of Cu-AI-Ni is the one that obtained the biggest grain size. Through MEB together with the analysis by EDS and the mapping of the elements that constitute each alloy, show that the three foundries were alloyed, moreover the presence of aggregates was also observed in the Foundries 2 and 3. These results by means of the analysis of XRD corroborate that these alloys have more of two elements. Relating the microstructural properties with those mechanical show us that as minor was the grain size, better they were his mechanical properties, in this case that of the quaternary alloy. With regard to the test of Rockwell hardness the Foundry 1 were the softest with the temper treatment, while that the Foundries 2 and 3 were the hardest with this same treatment, being still harder the Foundry 2 but with very little difference, for what great

Relationship between microstructure, cytotoxicity and corrosion properties of a Cu-Al-Ni shape memory alloy.

Science.gov (United States)

Colić, Miodrag; Rudolf, Rebeka; Stamenković, Dragoslav; Anzel, Ivan; Vucević, Dragana; Jenko, Monika; Lazić, Vojkan; Lojen, Gorazd

2010-01-01

Cu-Al-Ni shape memory alloys (SMAs) have been investigated as materials for medical devices, but their biomedical application is still limited. The aim of this work was to compare the microstructure, corrosion and cytotoxicity in vitro of a Cu-Al-Ni SMA. Rapidly solidified (RS) thin ribbons, manufactured via melt spinning, were used for the tests. The control alloy was a permanent mould casting of the same composition, but without shape memory effect. The results show that RS ribbons are significantly more resistant to corrosion compared with the control alloy, as judged by the lesser release of Cu and Ni into the conditioning medium. These results correlate with the finding that RS ribbons were not cytotoxic to L929 mouse fibroblasts and rat thymocytes. In addition, the RS ribbon conditioning medium inhibited cellular proliferation and IL-2 production by activated rat splenocytes to a much lesser extent. The inhibitory effects were almost completely abolished by conditioning the RS ribbons in culture medium for 4 weeks. Microstructural analysis showed that RS ribbons are martensitic, with boron particles as a minor phase. In contrast, the control Cu-Al-Ni alloy had a complex multiphase microstructure. Examination of the alloy surfaces after conditioning by energy dispersive X-ray and Auger electron spectroscopy showed the formation of Cu and Al oxide layers and confirmed that the metals in RS ribbons are less susceptible to oxidation and corrosion compared with the control alloy. In conclusion, these results suggest that rapid solidification significantly improves the corrosion stability and biocompatibility in vitro of Cu-Al-Ni SMA ribbons.

Internal friction of Ti-Ni-Cu ternary shape memory alloys

International Nuclear Information System (INIS)

Yoshida, I.; Monma, D.; Iino, K.; Ono, T.; Otsuka, K.; Asai, M.

2004-01-01

Low frequency internal friction was measured on three specimens of Ti-Ni-Cu ternary alloys, the Cu content varying from 10 to 20 at.%, while Ti content was fixed at 50 at.%. The internal friction spectrum consists mainly of two peaks, a sharper one associated with the B2-B19 transformation and the other one at around 250 K, which is much broader and higher than the former. The peak height of the latter is 0.2 for the specimen containing 20% Cu, which shows that this alloy can be an excellent high damping material. Transformation behavior was studied by electrical resistivity, thermopower and DSC measurements, and was compared with the result of internal friction measurements. Solution treatment at higher temperatures lowers the internal friction peak markedly. Scanning electron microscopy observation reveals that the behaviors of precipitates are different for different solution treatment temperature, suggesting that the precipitation behavior is crucial in the damping properties

Effects of Alloying Elements (Mo, Ni, and Cu on the Austemperability of GGG-60 Ductile Cast Iron

Directory of Open Access Journals (Sweden)

Erkan Konca

2017-08-01

Full Text Available The interest in austempered ductile irons (ADI is continuously increasing due to their various advantageous properties over conventional ductile irons and some steels. This study aimed to determine the roles of alloying elements Ni, Cu, and Mo, on the austemperability of GGG-60 ductile cast iron. Two different sets of GGG-60 (EN-GJS-600-3 samples, one set alloyed with Ni and Cu and the other set alloyed with Mo, Ni, and Cu, were subjected to austempering treatments at 290 °C, 320 °C, and 350 °C. A custom design heat treatment setup, consisting of two units with the top unit (furnace serving for austenitizing and the 200 L capacity bottom unit (stirred NaNO2-KNO3 salt bath serving for isothermal treatment, was used for the experiments. It was found that austempering treatment at 290 °C increased the hardness of the Ni-Cu alloyed GGG-60 sample by about 44% without causing a loss in its ductility. In the case of the Mo-Ni-Cu alloyed sample, the increase in hardness due to austempering reached to almost 80% at the same temperature while some ductility was lost. Here, the microstructural investigation and mechanical testing results of the austempered samples are presented and the role of alloying elements (Mo, Ni, and Cu on the austemperability of GGG-60 is discussed.

Effect of Si addition on the glass-forming ability of a NiTiZrAlCu alloy

International Nuclear Information System (INIS)

Liang, W.Z.; Shen, J.; Sun, J.F.

2006-01-01

The effect of Si addition on the glass-forming ability (GFA) of a NiTiZrAlCu alloy was investigated by using differential scanning calorimetry (DSC), differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The maximum diameter of glassy rods increased from 0.5 mm for the Ni 42 Ti 20 Zr 25 Al 8 Cu 5 alloy (the base alloy) to 2.5 mm for the Ni 42 Ti 20 Zr 21.5 Al 8 Cu 5 Si 3.5 alloy and to 3 mm for the Ni 42 Ti 19 Zr 22.5 Al 8 Cu 5 Si 3.5 alloy, when prepared by using the copper mould casting. The GFA of the alloys can be assessed by the reduced glass transition temperature T rg (=T g /T l ) and a newly proposed parameter, δ(=T x /T l - T g ). An addition of a proper amount of Si and a minor substitution of Ti with Zr can enhance the GFA of the base alloy by suppressing the formation of primary Ni(TiZr) and (TiZr)(CuAl) 2 phases and inducing the composition close to eutectic

Electronic Topological Transitions in CuNiMnAl and CuNiMnSn under pressure from first principles study

Science.gov (United States)

Rambabu, P.; Kanchana, V.

2018-06-01

A detailed study on quaternary ordered full Heusler alloys CuNiMnAl and CuNiMnSn at ambient and under different compressions is presented using first principles electronic structure calculations. Both the compounds are found to possess ferromagnetic nature at ambient with magnetic moment of Mn being 3.14 μB and 3.35 μB respectively in CuNiMnAl and CuNiMnSn. The total magnetic moment for both the compounds is found to decrease under compression. Fermi surface (FS) topology change is observed in both compounds under pressure at V/V0 = 0.90, further leading to Electronic Topological Transitions (ETTs) and is evidenced by the anomalies visualized in density of states and elastic constants under compression.

Note: Erosion of W-Ni-Fe and W-Cu alloy electrodes in repetitive spark gaps.

Science.gov (United States)

Wu, Jiawei; Han, Ruoyu; Ding, Weidong; Qiu, Aici; Tang, Junping

2018-02-01

A pair of W-Ni-Fe and W-Cu electrodes were tested under 100 kA level pulsed currents for 10 000 shots, respectively. Surface roughness and morphology characteristics of the two pairs of electrodes were obtained and compared. Experimental results indicated cracks divided the W-Cu electrode surface to polygons while the W-Ni-Fe electrode surface remained as a whole with pits and protrusions. Accordingly, the surface roughness of W-Ni-Fe electrodes increased to ∼3 μm while that of W-Cu electrodes reached ∼7 μm at the end of the test. The results reveal that the W-Ni-Fe alloy has a better erosion resistance and potential to be further applied in spark gaps.

Influence of the Si content on the microstructure and mechanical properties of Ti-Ni-Cu-Si-Sn nanocomposite alloys

Energy Technology Data Exchange (ETDEWEB)

Fornell, J., E-mail: Jordinafornell@gmail.com [Departament de Fisica, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Van Steenberge, N. [OCAS N.V., Pres. J.F. Kennedylaan 3, BE-9060 Zelzate (Belgium); Surinach, S.; Baro, M.D. [Departament de Fisica, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Sort, J. [Departament de Fisica, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Institucio Catalana de Recerca i Estudis Avancats (Spain)

2012-09-25

Highlights: Black-Right-Pointing-Pointer We study the effects of Si addition of Ti-Ni-Cu-Si-Sn alloy. Black-Right-Pointing-Pointer The microstructure evolution is correlated with the obtained mechanical and elastic properties. Black-Right-Pointing-Pointer Higher Young's modulus and larger hardness values are obtained in samples with higher Si contents. - Abstract: (Ti{sub 48}Ni{sub 32}Cu{sub 8}Si{sub 8}Sn{sub 4}){sub 100-x}Si{sub x} (x = 0, 2, 4 and 6) alloys were prepared by levitation melting mixtures of the high purity elements in an Ar atmosphere. Rods of 3 mm in diameter were obtained from the melt by copper mould casting. The effects of Si addition on the microstructure, elastic and mechanical properties of the Ti{sub 48}Ni{sub 32}Cu{sub 8}Si{sub 8}Sn{sub 4} alloy were investigated by scanning electron microscopy, X-ray diffraction, acoustic measurements and nanoindentation. The main phases composing the Ti{sub 48}Ni{sub 32}Cu{sub 8}Si{sub 8}Sn{sub 4} alloy are B2 NiTi, B19 Prime NiTi and tetragonal Ti{sub 2}Ni. Additional phases, like Ti{sub 5}Si{sub 3} or Ni{sub 2}Ti{sub 2}Si, become clearly visible in samples with higher Si contents. The microstructure evolution is correlated with the obtained mechanical and elastic properties. These alloys exhibit very high hardness values, which increase with the Si content, from 9 GPa (for x = 0) to around 10.5 GPa (for x = 6). The Young's modulus of Ti{sub 48}Ni{sub 32}Cu{sub 8}Si{sub 8}Sn{sub 4} (around 115 GPa) also increases significantly with Si addition, up to 160 GPa for x = 6.

A new Ti-Zr-Hf-Cu-Ni-Si-Sn bulk amorphous alloy with high glass-forming ability

Energy Technology Data Exchange (ETDEWEB)

Huang, Y.J. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Shen, J. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)]. E-mail: junshen@hit.edu.cn; Sun, J.F. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Yu, X.B. [Lab of Energy Science and Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)]. E-mail: yuxuebin@hotmail.com

2007-01-16

The effect of Sn substitution for Cu on the glass-forming ability was investigated in Ti{sub 41.5}Zr{sub 2.5}Hf{sub 5}Cu{sub 42.5-x}Ni{sub 7.5}Si{sub 1}Sn {sub x} (x = 0, 1, 3, 5, 7) alloys by using differential scanning calorimetry (DSC) and X-ray diffractometry. The alloy containing 5% Sn shows the highest glass-forming ability (GFA) among the Ti-Zr-Hf-Cu-Ni-Si-Sn system. Fully amorphous rod sample with diameters up to 6 mm could be successfully fabricated by the copper mold casting Ti{sub 41.5}Zr{sub 2.5}Hf{sub 5}Cu{sub 37.5}Ni{sub 7.5}Si{sub 1}Sn{sub 5} alloy. The activation energies for glass transition and crystallization for Ti{sub 41.5}Zr{sub 2.5}Hf{sub 5}Cu{sub 37.5}Ni{sub 7.5}Si{sub 1}Sn{sub 5} amorphous alloy are both larger than those values for the Sn-free alloy. The enhancement in GFA and thermal stability after the partial replacement of Cu by Sn may be contributed to the strong atomic bonding nature between Ti and Sn and the increasing of atomic packing density. The amorphous Ti{sub 41.5}Zr{sub 2.5}Hf{sub 5}Cu{sub 37.5}Ni{sub 7.5}Si{sub 1}Sn{sub 5} alloy also possesses superior mechanical properties.

Intermartensitic transitions in Ni-Mn-Fe-Cu-Ga Heusler alloys

International Nuclear Information System (INIS)

Khan, Mahmud; Gautam, Bhoj; Pathak, Arjun; Dubenko, Igor; Stadler, Shane; Ali, Naushad

2008-01-01

A series of Fe doped Ni 2 Mn 0.75-x Fe x Cu 0.25 Ga Heusler alloys have been investigated by means of x-ray diffraction, magnetizations, thermal expansion, and electrical resistivity measurements. In Ni 2 Mn 0.75 Cu 0.25 Ga, martensitic and ferromagnetic transitions occur at the same temperature. Partial substitution of Mn by Fe results in a decrease of the martensitic transition temperature, T M , and an increase of the ferromagnetic transition temperature, T C , resulting in separation of the two transitions. In addition to the martensitic transition, complete thermoelastic intermartensitic transformations have been observed in the Fe doped Ni 2 Mn 0.75-x Fe x Cu 0.25 Ga samples with x>0.04. An unusual transition is observed in the alloy with x = 0.04. The magnetization curve as a function of increasing temperature shows only one first-order transition in the temperature range 5-400 K, which is identified as a typical coupled magnetostructural martensitic transformation. The magnetization curve as a function of decreasing temperature shows three different transitions, which are characterized as the ferromagnetic transition, the martensitic transition and the intermartensitic transition.

Preparation of Copper (Cu)-Nickel (Ni) Alloy Thin Films for Bilayer Graphene Growth

Science.gov (United States)

2016-02-01

of each sample after annealing . Transene brand APS-100 etchant is used to completely wet etch away the unmasked portion of the Cu-Ni alloy, and...morphological changes in the metal surfaces such as roughness, grain size, and crystal orientation due to the effects of annealing temperature, hydrogen...post- annealed at 1000 °C for 30 min, 40% H2, 15 Torr.............5 Fig. 6 AFM imaging of Cu:Ni alloyed films with ratios of a) 6:1 , b) 4:1, and c) 3

Crystallization in Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk metallic glass under pressure

DEFF Research Database (Denmark)

Jiang, Jianzhong; Zhou, T.J.; Rasmussen, Helge Kildahl

2000-01-01

The effect of pressure on the crystallization behavior of the bulk metallic glass-forming Zr41.2Ti13.8Cu12.5Ni10Be22.5 alloy with a wide supercooled liquid region has been investigated by in situ high-pressure and high-temperature x-ray powder diffraction measurements using synchrotron radiation......)], reporting a decrease of the crystallization temperature under pressure in a pressure range of 0-6 GPa for the bulk glass Zr41Ti14Cu12.5Ni9Be22.5C1 alloy. Compressibility with a volume reduction of approximately 22% at room temperature does not induce crystallization in the Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk...... glass alloy. This indicates that the densification effect induced by pressure in the pressure range investigated plays a minor role in the crystallization behavior of this bulk glass alloy. The different crystallization behavior of the carbon-free and the carbon-containing glassy alloys has been...

Wetting behaviour of lead-free Sn-based alloys on Cu and Ni substrates

International Nuclear Information System (INIS)

Amore, S.; Ricci, E.; Borzone, G.; Novakovic, R.

2008-01-01

The present work was carried out in the framework of the study of new lead-free solder alloys for technical applications in electronic devices. In the focus of this characterisation the wetting behaviour of several Sn-rich alloys belonging to the In-Sn, Au-Sn and Cu-Sn systems has been studied by measuring the contact angle variations on Cu and Ni substrates as a function of time and temperature. The interface between the alloy and the substrate has been analysed by the use of optical microscopy and scanning electron microscopy combined with energy-dispersive X-ray spectrometry in order to study the reaction between the alloy and the solid substrate and the possible formation of different compounds at the interface. A remarkable effect of the two different substrates on the behaviour of the contact angle as a function of temperature and on the morphology of the interface between the liquid solder and the solid substrate was observed for the In-Sn and Cu-Sn, while the Au-Sn system shows a very similar wetting behaviour on Cu and Ni

Effect of Ta Additions on the Microstructure, Damping, and Shape Memory Behaviour of Prealloyed Cu-Al-Ni Shape Memory Alloys

Directory of Open Access Journals (Sweden)

Safaa N. Saud

2017-01-01

Full Text Available The influence of Ta additions on the microstructure and properties of Cu-Al-Ni shape memory alloys was investigated in this paper. The addition of Ta significantly affects the green and porosity densities; the minimum percentage of porosity was observed with the modified prealloyed Cu-Al-Ni-2.0 wt.% Ta. The phase transformation temperatures were shifted towards the highest values after Ta was added. Based on the damping capacity results, the alloy of Cu-Al-Ni-3.0 wt.% Ta has very high internal friction with the maximum equivalent internal friction value twice as high as that of the prealloyed Cu-Al-Ni SMA. Moreover, the prealloyed Cu-Al-Ni SMAs with the addition of 2.0 wt.% Ta exhibited the highest shape recovery ratio in the first cycle (i.e., 100% recovery, and when the number of cycles is increased, this ratio tends to decrease. On the other hand, the modified alloys with 1.0 and 3.0 wt.% Ta implied a linear increment in the shape recovery ratio with increasing number of cycles. Polarization tests in NaCl solution showed that the corrosion resistance of Cu-Al-Ni-Ta SMA improved with escalating Ta concentration as shown by lower corrosion current densities, higher corrosion potential, and formation of stable passive film.

Effect of Ta Additions on the Microstructure, Damping, and Shape Memory Behaviour of Prealloyed Cu-Al-Ni Shape Memory Alloys.

Science.gov (United States)

Saud, Safaa N; Hamzah, E; Bakhsheshi-Rad, H R; Abubakar, T

2017-01-01

The influence of Ta additions on the microstructure and properties of Cu-Al-Ni shape memory alloys was investigated in this paper. The addition of Ta significantly affects the green and porosity densities; the minimum percentage of porosity was observed with the modified prealloyed Cu-Al-Ni-2.0 wt.% Ta. The phase transformation temperatures were shifted towards the highest values after Ta was added. Based on the damping capacity results, the alloy of Cu-Al-Ni-3.0 wt.% Ta has very high internal friction with the maximum equivalent internal friction value twice as high as that of the prealloyed Cu-Al-Ni SMA. Moreover, the prealloyed Cu-Al-Ni SMAs with the addition of 2.0 wt.% Ta exhibited the highest shape recovery ratio in the first cycle (i.e., 100% recovery), and when the number of cycles is increased, this ratio tends to decrease. On the other hand, the modified alloys with 1.0 and 3.0 wt.% Ta implied a linear increment in the shape recovery ratio with increasing number of cycles. Polarization tests in NaCl solution showed that the corrosion resistance of Cu-Al-Ni-Ta SMA improved with escalating Ta concentration as shown by lower corrosion current densities, higher corrosion potential, and formation of stable passive film.

Synthesis and Characterization of High-Entropy Alloy AlFeCoNiCuCr by Laser Cladding

Directory of Open Access Journals (Sweden)

Xiaoyang Ye

2011-01-01

Full Text Available High-entropy alloys have been recently found to have novel microstructures and unique properties. In this study, a novel AlFeCoNiCuCr high-entropy alloy was prepared by laser cladding. The microstructure, chemical composition, and constituent phases of the synthesized alloy were characterized by SEM, EDS, XRD, and TEM, respectively. High-temperature hardness was also evaluated. Experimental results demonstrate that the AlFeCoNiCuCr clad layer is composed of only BCC and FCC phases. The clad layers exhibit higher hardness at higher Al atomic content. The AlFeCoNiCuCr clad layer exhibits increased hardness at temperature between 400–700°C.

INFLUENCE OF THE HOMOGENIZATION TEMPERATURE ON THE MICROSTRUCTURE AND PROPERTIES OF AlSi10CuNiMgMn ALLOY

Directory of Open Access Journals (Sweden)

Jaromir Cais

2017-03-01

Full Text Available The article examines the impact of changes in homogenization temperature in the hardening process on the microstructure of aluminum alloys. Samples where the research was conducted were cast from AlSi10CuNiMn alloy produced by gravity casting technology in metal mold. Subsequently, the castings were subjected to a heat treatment. In an experiment with changing temperature and staying time in the process of homogenization. The microstructure of the alloy was investigated by methods of light and electron microscopy. Examination of the microstructure has focused on changing the morphology of separated particles of eutectic silicon and intermetallic phases. Analysis of intermetallic phases was supplemented by an analysis of the chemical composition - EDS analysis. Effect of heat treatment on the properties investigated alloy was further complemented by Vickers microhardness. Investigated alloy is the result of longtime research conducted at Faculty of Production Technology and Management.

Fracture behaviour of Cu-Al-Ni shape memory alloys obtained by powder metallurgy

International Nuclear Information System (INIS)

Rodriguez, P. P.; Perez-Saez, R. B.; Recarte, V.; San Juan, J.M.; Ruano, O. A.; No, M. L.

2001-01-01

Polycrystalline Cu-Al-Ni shape memory alloys have been scarcely employed for technological applications due to their high brittleness. The development of a new elaboration technique based on powder metallurgy has recently overcome this problem, through the improvement of the ductility of the produced alloys without affecting its shape memory properties. The fracture behaviour of an alloy obtained using the elaboration technique has been studied by means of Scanning Electron Microscopy and mechanical testing. The results show a ductile fracture with a maximum strain close to 13%, which is the best fracture behaviour obtained for Cu-Al-Ni polycrystals. The microstructure of such alloys ha been studied by means of Transmission Electron Microscopy, showing a poligonyzed structure in which martensite plated passing through the subboundaries easily. (Author) 19 refs

GRAIN-REFINEMENT AND THE RELATED PHENOMENA IN QUATERNARY Cu-Al-Ni-Ti SHAPE MEMORY ALLOYS

OpenAIRE

Sugimoto , K.; Kamei , K.; Matsumoto , H.; Komatsu , S.; Akamatsu , K.; Sugimoto , T.

1982-01-01

It was reported that the addition of a small amount of titanium (0.5 - 3.99%) to a Cu-13.93%Al-3.36%Ni ternary alloy resulted in a remarkable grain-refining. The original grain-size of about 750 microns under hot-rolled and quenched conditions of the ternary alloy was reduced to that of the order of about 100 microns by addition of tiatanium. It was suggested that several technical improvements of the mechanical properties of Cu-Al-Ni shape memory alloys, such as better formability, less crac...

Corrosion Inhibition Study of Al-Cu-Ni Alloy in Simulated Sea-Water ...

African Journals Online (AJOL)

Akorede

ABSTRACT: A study on the inhibition of Al-Cu-Ni alloy in simulated ... which the percentage of Copper, and Nickel were kept .... proceed based on equation of reaction in eqn (4). Al .... Sodium-Modified A356.0-Type Al-Si-Mg Alloy in Simulated.

RF magnetron sputtered TiNiCu shape memory alloy thin film

International Nuclear Information System (INIS)

Fu Yongqing; Du Hejun

2003-01-01

Shape memory alloys (SMAs) offer a unique combination of novel properties, such as shape memory effect, super-elasticity, biocompatibility and high damping capacity, and thin film SMAs have the potential to become a primary actuating mechanism for micro-actuators. In this study, TiNiCu films were successfully prepared by mix sputtering of a Ti 55 Ni 45 target with a separated Cu target. Crystalline structure, residual stress and phase transformation properties of the TiNiCu films were investigated using X-ray diffraction (XRD), differential scanning calorimeter (DSC), and curvature measurement methods. Effects of the processing parameters on the film composition, phase transformation and shape-memory effects were analyzed. Results showed that films prepared at a high Ar gas pressure exhibited a columnar structure, while films deposited at a low Ar gas pressure showed smooth and featureless structure. Chemical composition of TiNiCu thin films was dependent on the DC power of copper target. DSC, XRD and curvature measurement revealed clearly the martensitic transformation of the deposited TiNiCu films. When the free-standing film was heated and cooled, a 'two-way' shape-memory effect can be clearly observed

Discontinuous precipitation and ordering in Ni2V-Cu alloys

International Nuclear Information System (INIS)

Sukhanov, V.D; Boyarshinova, T.S.; Shashkov, O.D.

1986-01-01

Ni-V-Cu system alloys were used to investigate the effect of ordering on over-saturated solid solution decomposition. It was discovered that ordering in the process of grain boundary migration (discontinuous disordering), stimulated changing of continuous precipitation mechanism for discontinuous one

Kinetic study of the annealing reactions in Cu-Ni-Fe alloys; Estudio cinetico de las reacciones de recocido en aleaciones de Cu-Ni-Fe

Energy Technology Data Exchange (ETDEWEB)

Donoso, E.

2014-07-01

The thermal aging of a Cu-45Ni-4Fe, Cu-34Ni-11Fe and Cu-33Ni-22Fe alloys tempered from 1173 K have been studied from Differential Scanning Calorimetry (DSC) and microhardness measurements. The analysis of DSC curves, from room temperature to 950 K, shows the presence of one exothermic reaction associated to the formation of FeNi{sub 3} phase nucleating from a modulate structure, and one endothermic peak attributed to dissolution of this phase. Kinetic parameters were obtained using the usual Avrami-Erofeev equation, modified Kissinger method and integrated kinetic functions. Microhardness measurements confirmed the formation and dissolution of the FeNi{sub 3} phase. (Author)

The pseudoelasticity of a Ni45Ti50Cu5 alloy

International Nuclear Information System (INIS)

Ranucci, T.; Airoldi, G.

2000-01-01

Since several years the Ni (50-X) Ti 50 Cu X alloys are attentively considered for the interesting features related to the B2=>B19' transformation involved in the pseudoelastic behavior. In contrast with the binary NiTi, where two martensitic transformations, B2=>R-phase and R-phase=>B19' can overlap, in the ternary alloy a single transformation is expected with a narrower hysteresis. The pseudoelastic behavior of a Ni 45 Ti 50 Cu 5 is here thoroughly investigated both as a function of different thermal treatments and of the maximum applied strain. The minimum hysteresis width of the pseudoelastic cycle appears for a thermal treatment of 450 C and decreases with stress cycling. The stress induced transformation involves, however, a single process whenever the maximum applied strain is smaller than the transformation strain. When the attained strain exceeds the transformation strain, another transformation sets in as supported by electrical resistance measurements performed concomitantly to stress-strain tests. (orig.)

Effect of processing of mechanical alloying and powder metallurgy on microstructure and properties of Cu-Al-Ni-Mn alloy

International Nuclear Information System (INIS)

Xiao Zhu; Li Zhou; Fang Mei; Xiong Shiyun; Sheng Xiaofei; Zhou Mengqi

2008-01-01

The fabrication conditions of Cu-Al-Ni-Mn alloy powder by mechanical alloying and powder metallurgy have been systematically studied. The mechanically alloyed powder (MAed powder) was fabricated at a speed between 100 rpm and 300 rpm for various milling times with and without process control agent (PCA). With an increasing of milling time, the size of crystallite grain decreases. Only the Cu diffraction pattern appear as the rotation speed is up to 300 rpm for 25 h. The elemental powders with PCA agglomerate slightly, but the degree of alloying is lower than that without PCA. The shape memory recovery of the quenched sample hot-extruded at extrusion rate of 50:1 is measured to be 100% recovered in 250 deg. C oil bath for 40 s after deformed to 4.0%. After aging at 120 deg. C for 10 days, the shape memory recovery of the alloy remains 98%

Glass formation and crystallization of Zr53Cu21Al10Ni8Ti8 alloy

International Nuclear Information System (INIS)

Neogy, S.; Tewari, R.; Srivastava, D.; Dey, G.K.; Banerjee, S.; Vaibhaw, K.; Ranganathan, S.

2010-01-01

In the present study, transmission electron microscopy techniques, like micro-diffraction, high resolution and fluctuation microscopy, have been employed to carry out detailed investigation of as-solidified and crystallized microstructures of the Zr 53 Cu 21 Al 10 Ni 8 Ti 8 alloy synthesized using melt spinning, suction casting and copper mould casting techniques. Samples produced by copper mould casting technique showed partially crystalline microstructure whereas the other techniques resulted in complete amorphous microstructures. High-resolution microscopy established that the dendrites of the big cube phase in partially crystalline glass grew by atomistic ledges. The other crystalline bct Zr 2 Ni phase, present in partially crystalline glass and also in all the crystallized microstructures, showed various types of internal faults depending upon the crystallite size. Fluctuation microscopy established that oxygen plays a major role in determining the degree of medium range order in glassy phases. In addition, variation in oxygen content changed the crystallization behaviour of glasses from a single to multiple events

A study of the composition and microstructure of nanodispersed Cu-Ni alloys obtained by different routes from copper and nickel oxides

Energy Technology Data Exchange (ETDEWEB)

Cangiano, Maria de los A; Ojeda, Manuel W., E-mail: mojeda@unsl.edu.ar; Carreras, Alejo C.; Gonzalez, Jorge A.; Ruiz, Maria del C

2010-11-15

Mixtures of CuO and NiO were prepared by two different techniques, and then the oxides were reduced with H{sub 2}. Method A involved the preparation of mechanical mixtures of CuO and NiO using different milling and pelletizing processes. Method B involved the chemical synthesis of the mixture of CuO and NiO. The route used to prepare the copper and nickel oxide mixture was found to have great influence on the characteristics of bimetallic Cu-Ni particles obtained. Observations performed using the X-ray diffraction (XRD) technique showed that although both methods led to the Cu-Ni solid solution, the diffractogram of the alloy obtained with method A revealed the presence of NiO together with the alloy. The temperature-programmed reduction (TPR) experiments indicated that the alloy is formed at lower temperatures when using method B. The scanning electron microscopy (SEM) studies revealed notable differences in the morphology and size distribution of the bimetallic particles synthesized by different routes. The results of the electron probe microanalysis (EPMA) studies evidenced the existence of a small amount of oxygen in both cases and demonstrated that the alloy synthesized using method B presented a homogeneous composition with a Cu-Ni ratio close to 1:1. On the contrary, the alloy obtained using method A was not homogeneous in all the volume of the solid. The homogeneity depended on the mechanical treatment undergone by the mixture of the oxides. - Research Highlights: {yields}Study of the properties of Cu-Ni alloys synthesized by two different routes. {yields}Mixtures of Cu and Ni oxides prepared by two techniques were reduced with H{sub 2}. {yields}Mixtures of oxides were obtained by a mechanical process and the citrate-gel route. {yields}The characterizations were carried out by TPR, XRD, SEM and EPMA. {yields}The route used to prepare oxide mixtures influences on the Cu-Ni alloy obtained.

A study of the composition and microstructure of nanodispersed Cu-Ni alloys obtained by different routes from copper and nickel oxides

International Nuclear Information System (INIS)

Cangiano, Maria de los A; Ojeda, Manuel W.; Carreras, Alejo C.; Gonzalez, Jorge A.; Ruiz, Maria del C

2010-01-01

Mixtures of CuO and NiO were prepared by two different techniques, and then the oxides were reduced with H 2 . Method A involved the preparation of mechanical mixtures of CuO and NiO using different milling and pelletizing processes. Method B involved the chemical synthesis of the mixture of CuO and NiO. The route used to prepare the copper and nickel oxide mixture was found to have great influence on the characteristics of bimetallic Cu-Ni particles obtained. Observations performed using the X-ray diffraction (XRD) technique showed that although both methods led to the Cu-Ni solid solution, the diffractogram of the alloy obtained with method A revealed the presence of NiO together with the alloy. The temperature-programmed reduction (TPR) experiments indicated that the alloy is formed at lower temperatures when using method B. The scanning electron microscopy (SEM) studies revealed notable differences in the morphology and size distribution of the bimetallic particles synthesized by different routes. The results of the electron probe microanalysis (EPMA) studies evidenced the existence of a small amount of oxygen in both cases and demonstrated that the alloy synthesized using method B presented a homogeneous composition with a Cu-Ni ratio close to 1:1. On the contrary, the alloy obtained using method A was not homogeneous in all the volume of the solid. The homogeneity depended on the mechanical treatment undergone by the mixture of the oxides. - Research Highlights: →Study of the properties of Cu-Ni alloys synthesized by two different routes. →Mixtures of Cu and Ni oxides prepared by two techniques were reduced with H 2 . →Mixtures of oxides were obtained by a mechanical process and the citrate-gel route. →The characterizations were carried out by TPR, XRD, SEM and EPMA. →The route used to prepare oxide mixtures influences on the Cu-Ni alloy obtained.

First-principles theory of short-range order in size-mismatched metal alloys: Cu-Au, Cu-Ag, and Ni-Au

International Nuclear Information System (INIS)

Wolverton, C.; Ozolins, V.; Zunger, A.

1998-01-01

We describe a first-principles technique for calculating the short-range order (SRO) in disordered alloys, even in the presence of large anharmonic atomic relaxations. The technique is applied to several alloys possessing large size mismatch: Cu-Au, Cu-Ag, Ni-Au, and Cu-Pd. We find the following: (i) The calculated SRO in Cu-Au alloys peaks at (or near) the left-angle 100 right-angle point for all compositions studied, in agreement with diffuse scattering measurements. (ii) A fourfold splitting of the X-point SRO exists in both Cu 0.75 Au 0.25 and Cu 0.70 Pd 0.30 , although qualitative differences in the calculated energetics for these two alloys demonstrate that the splitting in Cu 0.70 Pd 0.30 may be accounted for by T=0 K energetics while T≠0 K configurational entropy is necessary to account for the splitting in Cu 0.75 Au 0.25 . Cu 0.75 Au 0.25 shows a significant temperature dependence of the splitting, in agreement with recent in situ measurements, while the splitting in Cu 0.70 Pd 0.30 is predicted to have a much smaller temperature dependence. (iii) Although no measurements exist, the SRO of Cu-Ag alloys is predicted to be of clustering type with peaks at the left-angle 000 right-angle point. Streaking of the SRO peaks in the left-angle 100 right-angle and left-angle 1 (1) /(2) 0 right-angle directions for Ag- and Cu-rich compositions, respectively, is correlated with the elastically soft directions for these compositions. (iv) Even though Ni-Au phase separates at low temperatures, the calculated SRO pattern in Ni 0.4 Au 0.6 , like the measured data, shows a peak along the left-angle ζ00 right-angle direction, away from the typical clustering-type left-angle 000 right-angle point. (v) The explicit effect of atomic relaxation on SRO is investigated and it is found that atomic relaxation can produce significant qualitative changes in the SRO pattern, changing the pattern from ordering to clustering type, as in the case of Cu-Ag. copyright 1998 The American

Polycrystalline oxides formation during transient oxidation of (001) Cu-Ni binary alloys studied by in situ TEM and XRD

International Nuclear Information System (INIS)

Yang, J.C.; Li, Z.Q.; Sun, L.; Zhou, G.W.; Eastman, J.A.; Fong, D.D.; Fuoss, P.H.; Baldo, P.M.; Rehn, L.E.; Thompson, L.J.

2009-01-01

The nucleation and growth of Cu 2 O and NiO islands due to oxidation of Cu x Ni 1-x (001) films were monitored, at various temperatures, by in situ ultra-high vacuum (UHV) transmission electron microscopy (TEM) and in situ synchrotron X-ray diffraction (XRD). In remarkable contrast to our previous observations of Cu and Cu-Au oxidation, irregular-shaped polycrystalline oxide islands formed with respect to the Cu-Ni alloy film, and an unusual second oxide nucleation stage was noted. In situ XRD experiments revealed that NiO formed first epitaxially, then other orientations appeared, and finally polycrystalline Cu 2 O developed as the oxidation pressure was increased. The segregation of Ni and Cu towards or away, respectively, from the alloy surface during oxidation could disrupt the surface and cause polycrystalline oxide formation.

Stability of rapidly quenched and hydrogenated Mg-Ni-Y and Mg-Cu-Y alloys in extreme alkaline medium

International Nuclear Information System (INIS)

Gebert, A.; Khorkounov, B.; Wolff, U.; Mickel, Ch.; Uhlemann, M.; Schultz, L.

2006-01-01

Amorphous-nanocrystalline Mg 50 Ni 30 Y 20 and Mg 63 Ni 30 Y 7 and amorphous Mg 65 Cu 25 Y 10 alloys were produced by melt-spinning and characterized regarding their microstructure and thermal behaviour using XRD, TEM and DSC. Their electrochemical behaviour in the as-quenched state and after hydrogen charging at -25 mA/cm 2 for up to 20 h was studied in electrolytes with pH 5-7 and 13, but mainly in a battery electrolyte: 6 M KOH with pH 14.8 by means of anodic and cathodic polarization measurements. In the as-quenched state, the highest alloys stability was observed at pH 13. At pH 14.8, gradual oxidation and dissolution of copper or nickel governs the anodic behaviour before a passive state is attained. The dissolution of nickel is much more inhibited than that of copper due to its lower tendency to form soluble oxidized ions and to a stabilizing effect of higher fractions of yttrium in the alloy on the passivation. By galvanostatic charging, the Mg 65 Cu 25 Y 10 alloy shows the highest hydrogen absorption capacity followed by Mg 50 Ni 30 Y 20 and Mg 63 Ni 30 Y 7 . During the charging process, the alloys exhibit a change in the surface state chemistry, i.e. an enrichment of nickel- or copper-rich species, causing preferential oxidation and dissolution during subsequent exposure under free corrosion and anodic conditions. Mg-Ni-Y alloys demonstrate a higher stability during this treatment in extreme alkaline medium. The reasons for this and consequences regarding the use as electrode materials are discussed in detail

Site determination of Ni atoms in Cu-Al-Ni shape memory alloys by electron channelling enhanced microanalysis

International Nuclear Information System (INIS)

Nakata, Yoshiyuki; Tadaki, Tsugio; Shimizu, Ken-ichi

1990-01-01

The crystallographic site of Ni atoms in the parent phase of differently heat-treated Cu-28.6Al-3.7Ni (at.%) shape memory alloys has been examined by electron channelling enhanced microanalysis (ALCHEMI) in order to clarify effects of heat-treatments on the Ni atom site and M s temperature. The heat-treatments were as follows: (a) Quenching into a 10% NaOH solution at 263 K, (b) Quenching into hot water at 363 K and (c) Aging at 523 K for 3.6 ks after treatment (b). The M s temperatures of specimens (a), (b) and (c) were 158, 185 and 259 K, respectively, increasing with lowering quenching rate or aging. ALCHEMI revealed that Ni atoms occupied an identical site in all the three kinds of specimens: The Ni atoms were located at the nearest neighbor sites around Al atoms. This preferential occupation of Ni atoms was attributed to the strong binding force between Ni and Al atoms. Thus, the change in M s temperature due to different heat-treatments was not directly related to the crystallographic site of Ni atoms, but might be caused by the ordering between the next nearest neighbor Cu and Al atoms. (author)

Shape memory characteristics and mechanical properties of powder metallurgy processed Ti50Ni40Cu10 alloy.

Science.gov (United States)

Kim, Yeon-Wook

2014-10-01

Ti-Ni-Cu alloy powders were prepared by gas atomization and porous bulk specimens were fabricated by spark plasma sintering (SPS). The microstructure of as-solidified powders exhibited a cellular structure and they contained a high density of nano-sized porosities which were located in the intercellular regions. XRD analysis showed that one-step martensitic transformation of B2-B19 occurred in all alloy powders and SPS specimens. When the martensitic transformation start temperature (M(s)) and austenite transformation finish temperature (A(f)) were determined in order to analyze the dependence of powder size on transformation temperatures, the M(s) increased slightly from -17.5 degrees C to - 14.6 degrees C as increasing the powder size ranging from between 25 and 50 μm to ranging between 100 and 150 μm. However, the M(s) and A(f) of the as-atomized powders is much smaller than those of SPS specimens and the M(s) of porous specimen was about 10.9 degrees C. Loading-unloading compressive tests were carried out to investigate the mechanical properties of porous Ti-Ni-Cu specimen. The specimen was compressed to the strain of 6% at a temperature higher than A,. After unloading, the residual strain was 2.1%. After the compressed specimen was heated to 60 degrees C and held for 30 minutes and then cooled to room temperature, the changes in the length of the specimens were measured. Then it was found that the recovered strain ascribed to shape memory effect was 1.5%.

Synthesis and magnetic properties of multilayer Ni/Cu and NiFe/Cu ...

Indian Academy of Sciences (India)

The diameter of wires can be easily varied by pore size of alumina, ranging ... saturated HgCl2 solution to remove the remaining Al, and then dipped in 5 wt% ... for NiFe alloy it is 1.3 V, that is higher than for Ni/Cu nanowires to diminish Cu.

Structural stability of Pd40Cu30Ni10P20 metallic glass in supercooled liquid region

International Nuclear Information System (INIS)

Jiang, J.Z.; Saksl, K.

2004-01-01

Phase separation of bulk and ribbon Pd 40 Cu 30 Ni 10 P 20 glasses, annealed in the supercooled liquid region at ambient pressure and high pressures, has been studied by means of differential scanning calorimetry (DSC) and X-ray diffraction techniques. DSC measurements show only one glass transition event in all annealed samples, indicating that no phase separation occurs in the alloy annealed in the supercooled liquid region. Phase analyses reveal at least six crystalline phases in the crystallized sample: monoclinic, tetragonal Cu 3 Pd-like, rhombohedral, fcc-Ni 2 Pd 2 P, fcc-(Ni, Pd) solid solution, and body-centered tetragonal (bct) Ni 3 P-like phases. Annealing treatments under external pressures in the vicinity of the glass transition temperature neither induce phase separation nor alter the glass transition temperature of the Pd 40 Cu 30 Ni 10 P 20 bulk glass

Effect of Ti content on structure and properties of Al2CrFeNiCoCuTix high-entropy alloy coatings

International Nuclear Information System (INIS)

Qiu, X.W.; Zhang, Y.P.; Liu, C.G.

2014-01-01

Highlights: • Al 2 CrFeNiCoCuTi x high-entropy alloy coatings were prepared by laser cladding. • Al 2 CrFeNiCoCuTi x coatings show excellent corrosion resistance and wear resistance. • Al 2 CrFeNiCoCuTi x coatings play a good protective effect on Q235 steel. • Ti element promotes the formation of a BCC structure in a certain extent. -- Abstract: The Al 2 CrFeNiCoCuTi x high-entropy alloy coatings were prepared by laser cladding. The structure, hardness, corrosion resistance, wear resistance and magnetic property were studied by metallurgical microscope, scanning electron microscopy with spectroscopy (SEM/EDS), X-ray diffraction, micro/Vickers hardness tester, electrochemical workstation tribometer and multi-physical tester. The result shows that, Al 2 CrFeNiCoCuTi x high-entropy alloy samples consist of the cladding zone, bounding zone, heat affected zone and substrate zone. The bonding between the cladding layer and the substrate of a good combination; the cladding zone is composed mainly of equiaxed grains and columnar crystal; the phase structure of Al 2 CrFeNiCoCuTi x high-entropy alloy coatings simple for FCC, BCC and Laves phase due to high-entropy affect. Ti element promotes the formation of a BCC structure in a certain extent. Compared with Q235 steel, the free-corrosion current density of Al 2 CrFeNiCoCuTi x high-entropy alloy coatings is reduced by 1–2 orders of magnitude, the free-corrosion potential is more “positive”. With the increasing of Ti content, the corrosion resistance of Al 2 CrFeCoCuNiTi x high-entropy alloy coatings enhanced in 0.5 mol/L HNO 3 solution. Compared with Q235 steel, the relative wear resistance of Al 2 CrFeCoCuNiTi x high-entropy alloy coatings has improved greatly; both the hardness and plasticity are affecting wear resistance. Magnetization loop shows that, Ti 0.0 high-entropy alloy is a kind of soft magnetic materials

Design and characterization of FeCrNiCoAlCu and FeCrNiCo(AlCu){sub 0,5} multicomponent alloys; Previsao e caracterizacao de ligas multicomponentes FeCrNiCoAlCu e FeCrNiCo(AlCu){sub 0,5}

Energy Technology Data Exchange (ETDEWEB)

Triveno Rios, Carlos; Artacho, Victor Falcao [Universidade Federal do ABC (CECS/UFABC), Santo Andre, SP (Brazil). Engenharia de Materiais

2014-07-01

High entropy alloys using multi-element main quasi-equivalent atomic proportions and generally forms single-phase solid solution and has the ability to enhance levels of strain hardening combined with high levels of plastic deformation at room temperature. In this work two high-entropy alloys with almost similar composition were studied and the factors influencing the formation of solid solution phases (δ atomic radius difference, ΔH{sub mix} mixing enthalpy, ΔS{sub mix} mixing entropy) were evaluated. The microstructure as-cast and the compositions of phases in the two alloys were analyzed by SEM and XRD. The mechanical characterization was realized by measurements of microhardness and cold compression test. The results showed that FeCrNiCo(AlCu){sub 0,5} and FeCrNiCoAlCu alloys with δ equal to 5,7 and 4,9, respectively, form alloys with solid solutions of high entropy. However, the presence of FC and BCCC structures greatly influence the mechanical properties. (author)

Microstructure and Tensile/Corrosion Properties Relationships of Directionally Solidified Al-Cu-Ni Alloys

Science.gov (United States)

Rodrigues, Adilson V.; Lima, Thiago S.; Vida, Talita A.; Brito, Crystopher; Garcia, Amauri; Cheung, Noé

2018-03-01

Al-Cu-Ni alloys are of scientific and technological interest due to high strength/high temperature applications, based on the reinforcement originated from the interaction between the Al-rich phase and intermetallic composites. The nature, morphology, size, volume fraction and dispersion of IMCs particles throughout the Al-rich matrix are important factors determining the resulting mechanical and chemical properties. The present work aims to evaluate the effect of the addition of 1wt%Ni into Al-5wt%Cu and Al-15wt%Cu alloys on the solidification rate, macrosegregation, microstructure features and the interrelations of such characteristics on tensile and corrosion properties. A directional solidification technique is used permitting a wide range of microstructural scales to be examined. Experimental growth laws relating the primary and secondary dendritic spacings to growth rate and solidification cooling rate are proposed, and Hall-Petch type equations are derived relating the ultimate tensile strength and elongation to the primary dendritic spacing. Considering a compromise between ultimate tensile strength and corrosion resistance of the examined alloys samples from both alloys castings it is shown that the samples having more refined microstructures are associated with the highest values of such properties.

Effect of iron content on the structure and mechanical properties of Al{sub 25}Ti{sub 25}Ni{sub 25}Cu{sub 25} and (AlTi){sub 60-x}Ni{sub 20}Cu{sub 20}Fe{sub x} (x=15, 20) high-entropy alloys

Energy Technology Data Exchange (ETDEWEB)

Fazakas, É., E-mail: eva.fazakas@bayzoltan.hu [WPI-Advaced Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-Ku, Sendai 980-8577 (Japan); Wigner Research Center for Physics, Hungarian Academy of Sciences, H-1525, P.O.B. 49 (Hungary); Bay Zoltán Nonprofit Ltd., For Applied Research H-1116 Budapest, Fehérvári út 130 (Hungary); Zadorozhnyy, V. [National University of Science and Technology «MISIS», Leninsky prosp., 4, Moscow 119049 (Russian Federation); Louzguine-Luzgin, D.V. [WPI-Advaced Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-Ku, Sendai 980-8577 (Japan)

2015-12-15

Highlights: • Three new refractory alloys namely: Al{sub 25}Ti{sub 25}Ni{sub 25}Cu{sub 25}, Al{sub 22.5}Ti{sub 22.5}Ni{sub 20}Cu{sub 20}Fe{sub 15} and Al{sub 20}Ti{sub 20}Ni{sub 20}Cu{sub 20}Fe{sub 20}, were produced by induction-melting and casting. • This kind of alloys exhibits high resistance to annealing softening. • Most the alloys in the annealed state possess even higher Vickers microhardness than the as-cast alloys. • The Al{sub 22.5}Ti{sub 22.5}Ni{sub 20}Cu{sub 20}Fe{sub 15} and Al{sub 20}Ti{sub 20}Ni{sub 20}Cu{sub 20}Fe{sub 20} alloys annealed at 973 K show the highest compressive stress and ductility values. - Abstract: In this work, we investigated the microstructure and mechanical properties of Al{sub 25}Ti{sub 25}Ni{sub 25}C{sub u25} Al{sub 22.5}Ti{sub 22.5}Ni{sub 20}Cu{sub 20}Fe{sub 15} and Al{sub 20}Ti{sub 20}Ni{sub 20}Cu{sub 20}Fe{sub 20} high entropy alloys, produced by arc melting and casting in an inert atmosphere. The structure of these alloys was studied by X-ray diffractometry and scanning electron microscopy. The as-cast alloys were heat treated at 773, 973 and 1173 K for 1800 s to investigate the effects of aging on the plasticity, hardness and elastic properties. Compared to the conventional high-entropy alloys the Al{sub 25}Ti{sub 25}Ni{sub 25}Cu{sub 25}, Al{sub 22.5}Ti{sub 22.5}Ni{sub 20}Cu{sub 20}Fe{sub 15} and Al{sub 20}Ti{sub 20}Ni{sub 20}Cu{sub 20}Fe{sub 20} alloys are relatively hard and ductile. Being heat treated at 973 K the Al{sub 22.5}Ti{sub 22.5}Ni{sub 20}Cu{sub 20}Fe{sub 15} alloy shows considerably high strength and relatively homogeneous deformation under compression. The plasticity, hardness and elastic properties of the studied alloys depend on the fraction and intrinsic properties of the constituent phases. Significant hardening effect by the annealing is found.

Discontinuous precipitation and ordering in Ni/sub 2/V-Cu alloys

Energy Technology Data Exchange (ETDEWEB)

Sukhanov, V D; Boyarshinova, T S; Shashkov, O D

1986-12-01

Ni-V-Cu system alloys were used to investigate the effect of ordering on over-saturated solid solution decomposition. It was discovered that ordering in the process of grain boundary migration (discontinuous disordering), stimulated changing of continuous precipitation mechanism for discontinuous one.

Glass forming ability: Miedema approach to (Zr, Ti, Hf)-(Cu, Ni) binary and ternary alloys

Energy Technology Data Exchange (ETDEWEB)

Basu, Joysurya [Department of Chemical, Materials and Biomolecular Engineering, 191 Auditorium Road, University of Connecticut, Storrs 06269, CT (United States)], E-mail: jbasu@engr.uconn.edu; Murty, B.S. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Ranganathan, S. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India)

2008-10-06

Miedema's approach has been useful in determining the glass forming composition range for a particular alloy system. The concept of mixing enthalpy and mismatch entropy can be used in order to quantify Inoue's criteria of bulk metallic glass formation. In the present study, glass forming composition range has been determined for different binary and ternary (Zr, Ti, Hf)-(Cu, Ni) alloys based on the mixing enthalpy and mismatch entropy calculations. Though copper and nickel appear next to each other in the periodic table, the glass forming ability of the copper and nickel bearing alloys is different. Thermodynamic analysis reveals that the glass forming behaviour of Zr and Hf is similar, whereas it is different from that of Ti. The smaller atomic size of Ti and the difference in the heat of mixing of Ti, Zr, Hf with Cu and Ni leads to the observed changes in the glass forming behaviour. Enthalpy contour plots can be used to distinguish the glass forming compositions on the basis of the increasing negative enthalpy of the composition. This method reveals the high glass forming ability of binary Zr-Cu, Hf-Cu, Hf-Ni systems over a narrow composition range.

Stability of mechanically alloyed vacancy ordered phase in Al{sub 70}Cu{sub 15}Ni{sub 15} alloy during annealing

Energy Technology Data Exchange (ETDEWEB)

Yadav, Thakur Prasad; Tiwari, Radhey Shyam; Srivastava, Onkar Nath [Department of Physics, Banaras Hindu University, Varanasi-221 005 (India); Mukhopadhyay, Nilay Krishna, E-mail: hepons@yahoo.co, E-mail: yadavtp@gmail.co [Department of Metallurgical Engineering, Institute of Technology, Banaras Hindu University, Varanasi-221 005 (India)

2010-04-01

A nano {tau}{sub 3} vacancy-ordered phase in the Al-Cu-Ni alloy system has been synthesized with a composition close to Al{sub 70}Cu{sub 15}Ni{sub 15} by mechanical alloying a mixture of elemental powder in a high-energy ball mill by varying milling time from 10 to 100 hours. The stability of nano-crystalline {tau}{sub 3} vacancy-ordered phase has been studied under thermal annealing in vacuum as well as in air. The x-ray diffraction and transmission electron microscopy techniques were employed for characterization of the milled and annealed samples. The powder after 100 h of milling was found to contain mostly nano {tau}{sub 3} phase with the partial ordering, and with crystallite sizes in the range of 10-20 nm along with a lattice strain of {approx}0.67 %. The milled powder, after annealing in vacuum at 700 {sup 0}C for 60 h, revealed the formation of a strain-free and ordered {tau}{sub 3} phase with a crystallite size of 80 nm, indicating grain coarsening. It is interesting to note that the milled powder annealed in air at 700 {sup 0}C for 60 h showed the formation of (Cu,Ni)Al{sub 2}O{sub 4} type spinel phase with the lattice parameter of 8.1 A and the lattice strain as 0.52 %. The average grain size of spinel phase was found to be {approx} 40 nm.

A study on crystalline phases present in the as-solidified and crystallized microstructures in Zr53Cu21Al10Ni8Ti8 alloy

International Nuclear Information System (INIS)

Neogy, S.; Tewari, R.; Srivastava, D.; Dey, G.K.

2011-01-01

In the present study the as-solidified and crystallized microstructures of Zr 53 Cu 21 Al 10 Ni 8 Ti 8 alloy have been examined in detail. Solidification was carried out by melt spinning, suction casting and copper mould casting techniques. The last technique yielded a partially crystalline microstructure, whereas, the other two techniques resulted in amorphous microstructures. (author)

On the evolution of Cu-Ni-rich bridges of Alnico alloys with tempering

Energy Technology Data Exchange (ETDEWEB)

Fan, M. [Department of Materials Science and Engineering, North Carolina State University, Campus Box 7907, Raleigh, NC 27695-7907 (United States); Liu, Y. [Department of Materials Science and Engineering, North Carolina State University, Campus Box 7907, Raleigh, NC 27695-7907 (United States); Analytical Instrumentation Facility, North Carolina State University, Raleigh, NC 27695 (United States); Jha, Rajesh; Dulikravich, George S. [Departments of Mechanical and Materials Engineering, MAIDROC, Florida International University, EC3462, 10555 West Flagler Street, Miami, FL 33174 (United States); Schwartz, J.; Koch, C.C. [Department of Materials Science and Engineering, North Carolina State University, Campus Box 7907, Raleigh, NC 27695-7907 (United States)

2016-12-15

Tempering is a critical step in Alnico alloy processing, yet the effects of tempering on microstructure have not been well studied. Here we report these effects, and in particular the effects on the Cu-Ni bridges. Energy-dispersive X-ray spectroscopy (EDS) maps and line scans show that tempering changes the elemental distribution in the Cu-Ni bridges, but not the morphology and distribution of Cu-bridges. The Cu concentration in the Cu-Ni bridges increases after tempering while other element concentrations decrease, especially Ni and Al. Furthermore, tempering sharpens the Cu bridge boundaries. These effects are primarily related to the large 2C{sub 44}/(C{sub 11}−C{sub 12}) ratio for Cu, largest of all elements in Alnico. In addition, the Ni-Cu loops around the α{sub 1} phases become inconspicuous with tempering. The diffusion of Fe and Co to the α{sub 1} phase during tempering, which increases the difference of saturation magnetization between the α{sub 1} and α{sub 2} phases, is observed by EDS. In summary, α{sub 1}, α{sub 2} and Cu-bridges are concentrated with their major elements during tempering which improves the magnetic properties. The formation of these features formed through elemental diffusion is discussed via energy theories. - Highlights: • Tempering changes the elemental distribution in the Cu-Ni bridges, but not morphology. • Cu concentration in the Cu-Ni bridges increases after tempering while others decrease. • These effects are related to the large 2C{sub 44}/(C{sub 11}−C{sub 12}) ratio for Cu. • The Ni-Cu loops around the α{sub 1} phases become inconspicuous with tempering. • The diffusion of Fe and Co to the α{sub 1} phase during tempering is observed by EDS.

Atom probe characterization of precipitation in an aged Cu-Ni-P alloy

International Nuclear Information System (INIS)

Aruga, Yasuhiro; Saxey, David W.; Marquis, Emmanuelle A.; Cerezo, Alfred; Smith, George D.W.

2011-01-01

A temporal evolution of clusters associated with age hardening behavior in a Cu-Ni-P alloy during ageing at 250 o C for up to 100 ks after solution treatment has been carried out. A three-dimensional atom probe (3DAP) analysis has showed that Ni-P clusters are present in the as-quenched condition, and that the cluster density increases as the ageing time increases. The clusters have a wide range of Ni/P ratios when they are relatively small, whereas larger clusters exhibit a narrow distribution of the Ni/P ratio, approaching a ratio of approximately two. These results would indicate that the clusters with various Ni/P ratios form at the early stage of precipitation and the ratio approaches a value identical to that of the equilibrium phase at 250 o C as the clusters enlarge during ageing. -- Research highlights: → We characterize the clustering behavior in a Cu-Ni-P alloy during ageing at 250 o C. → The clusters have a wide range of Ni/P ratios when they are relatively small. → Larger clusters exhibit a narrow distribution of the ratio. → Hardness increases almost linearly with the logarithm of ageing time beyond 100s. → We believe increasing density and size of the clusters leads to the age hardening.

Crystal growth velocity in deeply undercooled Ni-Si alloys

Science.gov (United States)

Lü, Y. J.

2012-02-01

The crystal growth velocity of Ni95Si5 and Ni90Si10 alloys as a function of undercooling is investigated using molecular dynamics simulations. The modified imbedded atom method potential yields the equilibrium liquidus temperatures T L ≈ 1505 and 1387 K for Ni95Si5 and Ni90Si10 alloys, respectively. From the liquidus temperatures down to the deeply undercooled region, the crystal growth velocities of both the alloys rise to the maximum with increasing undercooling and then drop slowly, whereas the athermal growth process presented in elemental Ni is not observed in Ni-Si alloys. Instead, the undercooling dependence of the growth velocity can be well-described by the diffusion-limited model, furthermore, the activation energy associated with the diffusion from melt to interface increases as the concentration increases from 5 to 10 at.% Si, resulting in the remarkable decrease of growth velocity.

Magnetic properties of Co and Ni based alloy nanoparticles dispersed in a silica matrix

Energy Technology Data Exchange (ETDEWEB)

De Julian Fernandez, C. E-mail: dejulian@padova.infm.it; Sangregorio, C.; Mattei, G.; Maurizio, C.; Battaglin, G.; Gonella, F.; Lascialfari, A.; Lo Russo, S.; Gatteschi, D.; Mazzoldi, P.; Gonzalez, J.M.; D' Acapito, F

2001-04-01

A comparative study of the magnetic properties of Co and Ni based alloy nanoparticles (Ni-Co, Ni-Cu and Co-Cu) formed in a silica matrix by ion implantation is presented. Different ion doses and implantation sequences were realized in order to obtain different nanostructures. The structural and magnetic properties observed for the Cu{sub 50}Ni{sub 50} nanoparticles are similar to those of the Cu{sub 60}Ni{sub 40} bulk alloy. The crystal structure of Co{sub x}Ni{sub 1-x} (0{<=}x{<=}1) nanoparticles is similar to that of the corresponding bulk alloy. The magnetic properties depend on the ion-implanted dose and on the alloy composition. The samples prepared by implanting a 15x10{sup 16} ions/cm{sup 2} total dose contain nanoparticles, which are superparamagnetic at room temperature and their magnetic behavior is influenced by dipolar interparticle interactions. The magnetization of the CoNi samples at high magnetic field is larger than that of the corresponding bulk alloy and follows the same composition dependence of that quantity measured in the alloy.

Magnetic properties of Co and Ni based alloy nanoparticles dispersed in a silica matrix

International Nuclear Information System (INIS)

De Julian Fernandez, C.; Sangregorio, C.; Mattei, G.; Maurizio, C.; Battaglin, G.; Gonella, F.; Lascialfari, A.; Lo Russo, S.; Gatteschi, D.; Mazzoldi, P.; Gonzalez, J.M.; D'Acapito, F.

2001-01-01

A comparative study of the magnetic properties of Co and Ni based alloy nanoparticles (Ni-Co, Ni-Cu and Co-Cu) formed in a silica matrix by ion implantation is presented. Different ion doses and implantation sequences were realized in order to obtain different nanostructures. The structural and magnetic properties observed for the Cu 50 Ni 50 nanoparticles are similar to those of the Cu 60 Ni 40 bulk alloy. The crystal structure of Co x Ni 1-x (0≤x≤1) nanoparticles is similar to that of the corresponding bulk alloy. The magnetic properties depend on the ion-implanted dose and on the alloy composition. The samples prepared by implanting a 15x10 16 ions/cm 2 total dose contain nanoparticles, which are superparamagnetic at room temperature and their magnetic behavior is influenced by dipolar interparticle interactions. The magnetization of the CoNi samples at high magnetic field is larger than that of the corresponding bulk alloy and follows the same composition dependence of that quantity measured in the alloy

Explosive device of conduit using Ti Ni alloy

Directory of Open Access Journals (Sweden)

A. Yu. Kolobov

2014-01-01

Full Text Available Presently, materials have been developed which are capable at changing temperate to return significant inelastic deformations, exhibit rubber-like elasticity, convert heat into mechanical work, etc. The aggregate of these effects is usually called the shape memory effect.At present a great number of compounds and alloys with a shape memory effect has been known.These are alloys based on titanium nickelide (TiNi, copper-based alloys (Cu-Al, Cu-Sn, Cu-Al-Ni, Cu-Zn-Si, etc., gold and silver (Ag-Cd, Au-Ag-Cd, Au-Cd-Cu, Au-Zn-Cu, etc., manganese (Mn-Cr, Fe-Cu, Mn-Cu-Ni, Mn-Cu-Zr, Mn-Ni, etc., iron (Fe-Mn, Fe-Ni, Fe-Al, etc., and other compounds.The alloys based on titanium nickelide (nitinol are the most widely used.Alloys with shape memory effect find various applications in engineering and medicine, namely connecting devices, actuators, transformable design, multipurpose medical implants, etc.There is a task of breaking fuel conduit during separating the spacecraft from the rocket in space technology.The paper examines the procedure for design calculation of the separating device of conduit with the use of Ti-Ni alloy. This device can be used instead of the pyro-knives.The device contains two semi-rings from Ti-Ni alloy. In the place of break on the conduit an annular radius groove is made.At a temperature of martensite passage the semi-rings undergo deformation and in the strained state are set in the device. With heating to the temperature of the austenitic passage of bushing macro-deformation the energy stored by the nitinol bushing is great enough to break the conduit on the neck.The procedures of design calculation and response time of device are given.

Effect of alloying elements on solidification of primary austenite in Ni-Mn-Cu cast iron

Directory of Open Access Journals (Sweden)

A. Janus

2011-04-01

Full Text Available Within the research, determined were direction and intensity of alloying elements influence on solidification way (directional orvolumetric of primary austenite dendrites in hypoeutectic austenitic cast iron Ni-Mn-Cu. 50 cast shafts dia. 20 mm were analysed.Chemical composition of the alloy was as follows: 1.7 to 3.3 % C, 1.4 to 3.1 % Si, 2.8 to 9.9 % Ni, 0.4 to 7.7 % Mn, 0 to 4.6 % Cu, 0.14 to0.16 % P and 0.03 to 0.04 % S. The discriminant analysis revealed that carbon influences solidification of primary austenite dendrites most intensively. It clearly increases the tendency to volumetric solidification. Influence of the other elements is much weaker. This means that the solidification way of primary austenite dendrites in hypoeutectic austenitic cast iron Ni-Mn-Cu does not differ from that in an unalloyed cast iron.

Fabrication and nano-imprintabilities of Zr-, Pd- and Cu-based glassy alloy thin films

International Nuclear Information System (INIS)

Takenaka, Kana; Saidoh, Noriko; Nishiyama, Nobuyuki; Inoue, Akihisa

2011-01-01

With the aim of investigating nano-imprintability of glassy alloys in a film form, Zr 49 Al 11 Ni 8 Cu 32 , Pd 39 Cu 29 Ni 13 P 19 and Cu 38 Zr 47 Al 9 Ag 6 glassy alloy thin films were fabricated on Si substrate by a magnetron sputtering method. These films exhibit a very smooth surface, a distinct glass transition phenomenon and a large supercooled liquid region of about 80 K, which are suitable for imprinting materials. Moreover, thermal nano-imprintability of these obtained films is demonstrated by using a dot array mold with a dot diameter of 90 nm. Surface observations revealed that periodic nano-hole arrays with a hole diameter of 90 nm were successfully imprinted on the surface of these films. Among them, Pd-based glassy alloy thin film indicated more precise pattern imprintability, namely, flatter residual surface plane and sharper hole edge. It is said that these glassy alloy thin films, especially Pd-based glassy alloy thin film, are one of the promising materials for fabricating micro-machines and nano-devices by thermal imprinting.

Synergistic alloying effect on microstructural evolution and mechanical properties of Cu precipitation-strengthened ferritic alloys

International Nuclear Information System (INIS)

Wen, Y.R.; Li, Y.P.; Hirata, A.; Zhang, Y.; Fujita, T.; Furuhara, T.; Liu, C.T.; Chiba, A.; Chen, M.W.

2013-01-01

We report the influence of alloying elements (Ni, Al and Mn) on the microstructural evolution of Cu-rich nanoprecipitates and the mechanical properties of Fe–Cu-based ferritic alloys. It was found that individual additions of Ni and Al do not give rise to an obvious strengthening effect, compared with the binary Fe–Cu parent alloy, although Ni segregates at the precipitate/matrix interface and Al partitions into Cu-rich precipitates. In contrast, the co-addition of Ni and Al results in the formation of core–shell nanoprecipitates with a Cu-rich core and a B2 Ni–Al shell, leading to a dramatic improvement in strength. The coarsening rate of the core–shell precipitates is about two orders of magnitude lower than that of monolithic Cu-rich precipitates in the binary and ternary Fe–Cu alloys. Reinforcement of the B2 Ni–Al shells by Mn partitioning further improves the strength of the precipitation-strengthened alloys by forming ultrastable and high number density core–shell nanoprecipitates

Ageing effects in a Cu-Al-Ni shape memory alloy

Czech Academy of Sciences Publication Activity Database

Daříček, Tomáš; Lašek, Jiří; Zárubová, Niva; Novák, Václav; Bartuška, Pavel

2001-01-01

Roč. 11, - (2001), s. Pr8-179-Pr8-184 ISSN 1155-4339 R&D Projects: GA AV ČR IAA1010909; GA AV ČR IAA1010817 Institutional research plan: CEZ:AV0Z1010914 Keywords : Cu-Al-Ni alloy * shape memory * martensitic transformation * resistometry Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.401, year: 2001

Composition pathway in Fe-Cu-Ni alloy during coarsening

Science.gov (United States)

Mukherjee, Rajdip; Choudhury, Abhik; Nestler, Britta

2013-10-01

In this work the microstructure evolution for a two phase Fe-Cu-Ni ternary alloy is studied in order to understand the kinetic composition paths during coarsening of precipitates. We have employed a quantitative phase-field model utilizing the CALPHAD database to simulate the temporal evolution of a multi-particle system in a two-dimensional domain. The paths for the far-field matrix and for precipitate average compositions obtained from simulation are found to be rectilinear. The trends are compared with the corresponding sharp interface theory, in the context of an additional degree of freedom for determining the interface compositions due to the Gibbs-Thomson effect in a ternary alloy.

Effect of microstructure on the mechanical properties of as-cast Ti-Nb-Al-Cu-Ni alloys for biomedical application.

Science.gov (United States)

Okulov, I V; Pauly, S; Kühn, U; Gargarella, P; Marr, T; Freudenberger, J; Schultz, L; Scharnweber, J; Oertel, C-G; Skrotzki, W; Eckert, J

2013-12-01

The correlation between the microstructure and mechanical behavior during tensile loading of Ti68.8Nb13.6Al6.5Cu6Ni5.1 and Ti71.8Nb14.1Al6.7Cu4Ni3.4 alloys was investigated. The present alloys were prepared by the non-equilibrium processing applying relatively high cooling rates. The microstructure consists of a dendritic bcc β-Ti solid solution and fine intermetallic precipitates in the interdendritic region. The volume fraction of the intermetallic phases decreases significantly with slightly decreasing the Cu and Ni content. Consequently, the fracture mechanism in tension changes from cleavage to shear. This in turn strongly enhances the ductility of the alloy and as a result Ti71.8Nb14.1Al6.7Cu4Ni3.4 demonstrates a significant tensile ductility of about 14% combined with the high yield strength of above 820 MPa already in the as-cast state. The results demonstrate that the control of precipitates can significantly enhance the ductility and yet maintaining the high strength and the low Young's modulus of these alloys. The achieved high bio performance (ratio of strength to Young's modulus) is comparable (or even superior) with that of the recently developed Ti-based biomedical alloys. © 2013.

Fatigue of thin walled tubes in copper alloy CuNi10

DEFF Research Database (Denmark)

Lambertsen, Søren Heide; Damkilde, Lars; Jepsen, Michael S.

2016-01-01

The current work concerns the investigation of the fatigue resistance of CuNi10 tubes, which are frequently used in heat exchangers of large ship engines. The lifetime performances of the exchanger tubes are greatly affected by the environmental conditions, where especially the temperature...... by means of the ASTM E739 guideline and one-sided tolerance limits factor method. The tests show good fatigue resistance and the risk for a failure is low in aspect to the case of a ship heat exchanger....

Microstructural evolution of direct chill cast Al-15.5Si-4Cu-1Mg-1Ni-0.5Cr alloy during solution treatment

Directory of Open Access Journals (Sweden)

He Kezhun

2011-08-01

Full Text Available Heat treatment has important influence on the microstructure and mechanical properties of Al-Si alloys. The most common used heat treatment method for these alloys is solution treatment followed by age-hardening. This paper investigates the microstructural evolution of a direct chill (DC cast Al-15.5Si-4Cu-1Mg-1Ni-0.5Cr alloy after solution treated at 500, 510, 520 and 530℃, respectively for different times. The major phases observed in the as-cast alloy are α-aluminum dendrite, primary Si particle, eutectic Si, Al7Cu4Ni, Al5Cu2Mg8Si6, Al15(Cr, Fe, Ni, Cu4Si2 and Al2Cu. The Al2Cu phase dissolves completely after being solution treated for 2 h at 500℃, while the eutectic Si, Al5Cu2Mg8Si6 and Al15(Cr, Fe, Ni, Cu4Si2 phases are insoluble. In addition, the Al7Cu4Ni phase is substituted by the Al3CuNi phase. The α-aluminum dendrite network disappears when the solution temperature is increased to 530℃. Incipient melting of the Al2Cu-rich eutectic mixture occurrs at 520℃, and melting of the Al5Cu2Mg8Si6 and Al3CuNi phases is observed at a solution temperature of 530℃. The void formation of the structure and deterioration of the mechanical properties are found in samples solution treated at 530℃.

Study on the characteristics of the impingement erosion-corrosion for Cu-Ni Alloy sprayed coating(I)

International Nuclear Information System (INIS)

Lee, Sang Yeol; Lim, Uh Joh; Yun, Byoung Du

1998-01-01

Impingement erosion-corrosion test and electrochemical corrosion test in tap water(5000Ω-cm) and seawater(25Ω-cm). Thermal spraying coated Cu-Ni alloy on the carbon steel was carried out. The impingement erosion-corrosion behavior and electrochemical corrosion characteristics of the substrate(SS41) and Cu-Ni thermal spray coating were investigated. The erosion-corrosion control efficiency of Cu-Ni coating to substrate was also estimated quantitatively. Main results obtained are as follows : 1) Under the flow velocity of 13m/s, impingement erosion-corrosion of Cu-Ni coating is under the control of electrochemical corrosion factor rather than that of mechanical erosion. 2) The corrosion potential of Cu-Ni coating becomes more noble than that of substrate, and the current density of Cu-Ni coating under the corrosion potential is drained lowly than that of substrate. 3) The erosion-corrosion control efficiency of Cu-Ni coating to substrate is excellent in the tap water of high specific resistance solution, but it becomes dull in the seawater of low specific resistance. 4) The corrosion control efficiency of Cu-Ni coating to substrate in the seawater appears to be higher than that in the tap water

Alloying behavior of iron, gold and silver in AlCoCrCuNi-based equimolar high-entropy alloys

International Nuclear Information System (INIS)

Hsu, U.S.; Hung, U.D.; Yeh, J.W.; Chen, S.K.; Huang, Y.S.; Yang, C.C.

2007-01-01

High-entropy alloys are newly developed alloys that are composed, by definition, of at least five principal elements with concentrations in the range of 5-35 at.%. Therefore, the alloying behavior of any given principal element is significantly affected by all the other principal elements present. In order to elucidate this further, the influence of iron, silver and gold addition on the microstructure and hardness of AlCoCrCuNi-based equimolar alloys has been examined. The as-cast AlCoCrCuNi base alloy is found to have a dendritic structure, of which only solid solution FCC and BCC phases can be observed. The BCC dendrite has a chemical composition close to that of the nominal alloy, with a deficiency in copper however, which is found to segregate and form a FCC Cu-rich interdendrite. The microstructure of the iron containing alloys is similar to that of the base alloy. It is found that both of these aforementioned alloys have hardnesses of about 420 HV, which is equated to their similar microstructures. The as-cast ingot forms two layers of distinct composition with the addition of silver. These layers, which are gold and silver in color, are determined to have a hypoeutectic Ag-Cu composition and a multielement mixture of the other principal elements, respectively. This indicates the chemical incompatibility of silver with the other principal elements. The hardnesses of the gold (104 HV) and silver layers (451 HV) are the lowest and highest of the alloy systems studied. This is attributed to the hypoeutectic Ag-Cu composition of the former and the reduced copper content of the latter. Only multielement mixtures, i.e. without copper segregation, form in the gold containing alloy. Thus, it may be said that gold acts as a 'mixing agent' between copper and the other elements. Although several of the atom pairs in the gold containing alloy have positive enthalpies, thermodynamic considerations show that the high entropy contribution is sufficient to counterbalance

The Effect of Modulation Ratio of Cu/Ni Multilayer Films on the Fretting Damage Behaviour of Ti-811 Titanium Alloy.

Science.gov (United States)

Zhang, Xiaohua; Liu, Daoxin; Li, Xiaoying; Dong, Hanshan; Xi, Yuntao

2017-05-26

To improve the fretting damage (fretting wear and fretting fatigue) resistance of Ti-811 titanium alloy, three Cu/Ni multilayer films with the same modulation period thickness (200 nm) and different modulation ratios (3:1, 1:1, 1:3) were deposited on the surface of the alloy via ion-assisted magnetron sputtering deposition (IAD). The bonding strength, micro-hardness, and toughness of the films were evaluated, and the effect of the modulation ratio on the room-temperature fretting wear (FW) and fretting fatigue (FF) resistance of the alloy was determined. The results indicated that the IAD technique can be successfully used to prepare Cu/Ni multilayer films, with high bonding strength, low-friction, and good toughness, which yield improved room-temperature FF and FW resistance of the alloy. For the same modulation period (200 nm), the micro-hardness, friction, and FW resistance of the coated alloy increased, decreased, and improved, respectively, with increasing modulation ratio of the Ni-to-Cu layer thickness. However, the FF resistance of the coated alloy increased non-monotonically with the increasing modulation ratio. Among the three Cu/Ni multilayer films, those with a modulation ratio of 1:1 can confer the highest FF resistance to the Ti-811 alloy, owing mainly to their unique combination of good toughness, high strength, and low-friction.

Investigation of phase stability of novel equiatomic FeCoNiCuZn based-high entropy alloy prepared by mechanical alloying

Science.gov (United States)

Soni, Vinay Kumar; Sanyal, S.; Sinha, S. K.

2018-05-01

The present work reports the structural and phase stability analysis of equiatomic FeCoNiCuZn High entropy alloy (HEA) systems prepared by mechanical alloying (MA) method. In this research effort some 1287 alloy combinations were extensively studied to arrive at most favourable combination. FeCoNiCuZn based alloy system was selected on the basis of physiochemical parameters such as enthalpy of mixing (ΔHmix), entropy of mixing (ΔSmix), atomic size difference (ΔX) and valence electron concentration (VEC) such that it fulfils the formation criteria of stable multi component high entropy alloy system. In this context, we have investigated the effect of novel alloying addition in view of microstructure and phase formation aspect. XRD plots of the MA samples shows the formation of stable solid solution with FCC (Face Cantered Cubic) after 20 hr of milling time and no indication of any amorphous or intermetallic phase formation. Our results are in good agreement with calculation and analysis done on the basis of physiochemical parameters during selection of constituent elements of HEA.

Effect of protein adsorption on the corrosion behavior of 70Cu-30Ni alloy in artificial seawater.

Science.gov (United States)

Torres Bautista, Blanca E; Carvalho, Maria L; Seyeux, Antoine; Zanna, Sandrine; Cristiani, Pierangela; Tribollet, Bernard; Marcus, Philippe; Frateur, Isabelle

2014-06-01

Copper alloys often used in cooling circuits of industrial plants can be affected by biocorrosion induced by biofilm formation. The objective of this work was to study the influence of protein adsorption, which is the first step in biofilm formation, on the electrochemical behavior of 70Cu-30Ni (wt.%) alloy in static artificial seawater and on the chemical composition of oxide layers. For that purpose, electrochemical measurements performed after 1h of immersion were combined to surface analyses. A model is proposed to analyze impedance data. In the presence of bovine serum albumin (BSA, model protein), the anodic charge transfer resistance deduced from EIS data at Ecorr is slightly higher, corresponding to lower corrosion current. Without BSA, two oxidized layers are shown by XPS and ToF-SIMS: an outer layer mainly composed of copper oxide (Cu2O redeposited layer) and an inner layer mainly composed of oxidized nickel, with a global thickness of ~30nm. The presence of BSA leads to a mixed oxide layer (CuO, Cu2O, Ni(OH)2) with a lower thickness (~10nm). Thus, the protein induces a decrease of the dissolution rate at Ecorr and hence a decrease of the amount of redeposited Cu2O and of the oxide layer thickness. © 2013.

Effect of alloying elements on the shape memory properties of ductile Cu-Al-Mn alloys

International Nuclear Information System (INIS)

Sutou, Y.; Kainuma, R.; Ishida, K.

1999-01-01

The effect of alloying elements on the M s temperature, ductility and the shape memory properties of Cu-Al-Mn ductile shape memory (SM) alloys was investigated by differential scanning calorimetry, cold-rolling and tensile test techniques. It was found that the addition of Au, Si and Zn to the Cu 73 -Al 17 -Mn 10 alloy stabilized the martensite (6M) phase increasing the M s temperature, while the addition of Ag, Co, Cr, Fe, Ni, Sn and Ti decreased the stability of the martensite phase, decreasing the M s temperature. The SM properties were improved by the addition of Co, Ni, Cr and Ti. (orig.)

Physical properties of Zr50Cu40-xAl10Pdx bulk glassy alloys

International Nuclear Information System (INIS)

Wencka, M.; Jagodic, M.; Gradisek, A.; Kocjan, A.; Jaglicic, Z.; McGuiness, P.J.; Apih, T.; Yokoyama, Y.; Dolinsek, J.

2010-01-01

It was shown recently (Yokoyama et al. ) that the addition of a small amount of Pd to the Zr 50 Cu 40 Al 10 bulk glassy alloy (BGA) has a beneficial effect on fatigue-strength enhancement, where the composition Zr 50 Cu 37 Al 10 Pd 3 behaved in a resonant-like way by showing the highest fatigue limit of 1050 MPa and the minimum Vickers hardness. We performed a study of the magnetic properties, the specific heat, the electrical resistivity and the hydrogen-diffusion constant for a series of compositions Zr 50 Cu 40-x Al 10 Pd x (x = 0-7 at.%), in order to determine their physical properties and to check for the influence of the Pd content on these properties. The Zr 50 Cu 40-x Al 10 Pd x BGAs are nonmagnetic, conducting alloys, where the Pauli spin susceptibility of the conduction electrons is the only source of paramagnetism. The low-temperature specific heat indicates an enhancement of the conduction-electron effective mass m* below 5 K, suggesting that the Zr 50 Cu 40-x Al 10 Pd x BGAs are not free-electron-like compounds. The electrical resistivities of the Zr 50 Cu 40-x Al 10 Pd x BGAs amount to about 200 μΩ cm and show a small, negative temperature coefficient (NTC) with an increase from 300 to 2 K of 4%. The hydrogen self-diffusion constant D in hydrogen-loaded samples shows classical over-barrier-hopping temperature dependence and is of comparable magnitude to the related icosahedral and amorphous Zr 69.5 Cu 12 Ni 11 Al 7.5 hydrogen-storage alloys. No correlation between the investigated physical parameters and the Pd content of the samples could be observed.

A dilute Cu(Ni) alloy for synthesis of large-area Bernal stacked bilayer graphene using atmospheric pressure chemical vapour deposition

Energy Technology Data Exchange (ETDEWEB)

Madito, M. J.; Bello, A.; Dangbegnon, J. K.; Momodu, D. Y.; Masikhwa, T. M.; Barzegar, F.; Manyala, N., E-mail: ncholu.manyala@up.ac.za [Department of Physics, Institute of Applied Materials, SARCHI Chair in Carbon Technology and Materials, University of Pretoria, Pretoria 0028 (South Africa); Oliphant, C. J.; Jordaan, W. A. [National Metrology Institute of South Africa, Private Bag X34, Lynwood Ridge, Pretoria 0040 (South Africa); Fabiane, M. [Department of Physics, Institute of Applied Materials, SARCHI Chair in Carbon Technology and Materials, University of Pretoria, Pretoria 0028 (South Africa); Department of Physics, National University of Lesotho, P.O. Roma 180 (Lesotho)

2016-01-07

A bilayer graphene film obtained on copper (Cu) foil is known to have a significant fraction of non-Bernal (AB) stacking and on copper/nickel (Cu/Ni) thin films is known to grow over a large-area with AB stacking. In this study, annealed Cu foils for graphene growth were doped with small concentrations of Ni to obtain dilute Cu(Ni) alloys in which the hydrocarbon decomposition rate of Cu will be enhanced by Ni during synthesis of large-area AB-stacked bilayer graphene using atmospheric pressure chemical vapour deposition. The Ni doped concentration and the Ni homogeneous distribution in Cu foil were confirmed with inductively coupled plasma optical emission spectrometry and proton-induced X-ray emission. An electron backscatter diffraction map showed that Cu foils have a single (001) surface orientation which leads to a uniform growth rate on Cu surface in early stages of graphene growth and also leads to a uniform Ni surface concentration distribution through segregation kinetics. The increase in Ni surface concentration in foils was investigated with time-of-flight secondary ion mass spectrometry. The quality of graphene, the number of graphene layers, and the layers stacking order in synthesized bilayer graphene films were confirmed by Raman and electron diffraction measurements. A four point probe station was used to measure the sheet resistance of graphene films. As compared to Cu foil, the prepared dilute Cu(Ni) alloy demonstrated the good capability of growing large-area AB-stacked bilayer graphene film by increasing Ni content in Cu surface layer.

Ion scattering studies of ordered alloy surfaces: CuAu(1 0 0) and NiAl

International Nuclear Information System (INIS)

Beikler, R.; Taglauer, E.

2000-01-01

The composition and structure of alloy surfaces can differ from the corresponding bulk properties due to segregation and relaxation effects. We studied the (1 0 0) surface of the ordered alloy CuAu and amorphous Ni and Al by low-energy Ne + and Na + ion scattering. The interpretation of the experimental results is supported by numerical simulations using the MARLOWE code. In the CuAu system a certain geometry was found to be very sensitive to Au presence in the 2nd layer. Comparison with MARLOWE results also allows to study variations in the ion yields arising from neutralization effects. By trajectory analysis ion survival probabilities are estimated for Ni and Al

As cast precipitation microstructures in twin-roller melt-spun Cu{sub 90}Co{sub 10} alloys

Energy Technology Data Exchange (ETDEWEB)

Núñez-Coavas, H. [Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba (Argentina); Pozo-López, G., E-mail: gpozo@famaf.unc.edu.ar [Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); Instituto de Física Enrique Gaviola – CONICET (Argentina); Condó, A.M. [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); Centro Atómico Bariloche, Comisión Nacional de Energía Atómica, Instituto Balseiro, Universidad Nacional de Cuyo, Av. Bustillo 9500, 8400 San Carlos de Bariloche (Argentina); Urreta, S.E. [Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba (Argentina); and others

2016-12-15

��Microstructures of twin-rolled Cu{sub 90}Cu{sub 10} alloys are for the first time characterized. •Coherent Co-rich precipitates distribute forming dense colonies inside the grains. •No coexisting multilayer-like structures (spinodal or laminar phases) are detected. •Magnetic hysteresis arises from inter-particle interaction in these dense colonies. •Magnetoresistance level in these purely granular systems is low (1.6% at 300 K).

Mechanical Behavior and Fracture Properties of NiAl Intermetallic Alloy with Different Copper Contents

Directory of Open Access Journals (Sweden)

Tao-Hsing Chen

2016-03-01

Full Text Available The deformation behavior and fracture characteristics of NiAl intermetallic alloy containing 5~7 at% Cu are investigated at room temperature under strain rates ranging from 1 × 10−3 to 5 × 103 s−1. It is shown that the copper contents and strain rate both have a significant effect on the mechanical behavior of the NiAl alloy. Specifically, the flow stress increases with an increasing copper content and strain rate. Moreover, the ductility also improves as the copper content increases. The change in the mechanical response and fracture behavior of the NiAl alloy given a higher copper content is thought to be the result of the precipitation of β-phase (Ni,CuAl and γ'-phase (Ni,Cu3Al in the NiAl matrix.

Damage structures in fission-neutron irradiated Ni-based alloys at high temperatures

Science.gov (United States)

Yamakawa, K.; Shimomura, Y.

1999-01-01

The defects formed in Ni based (Ni-Si, Ni-Cu and Ni-Fe) alloys which were irradiated with fission-neutrons were examined by electron microscopy. Irradiations were carried out at 473 K and 573 K. In the 473 K irradiated specimens, a high density of large interstitial loops and small vacancy clusters with stacking fault tetrahedra (SFT) were observed. The number densities of these two types of defects did not strongly depend on the amount of solute atoms in each alloy. The density of the loops in Ni-Si alloys was much higher than those in Ni-Cu and Ni-Fe alloys, while the density of SFT only slightly depended on the kind of solute. Also, the size of the loops depended on the kinds and amounts of solute. In 573 K irradiated Ni-Cu specimens, a high density of dislocation lines developed during the growth of interstitial loops. In Ni-Si alloys, the number density and size of the interstitial loops changed as a function of the amount of solute. Voids were formed in Ni-Cu alloys but scarcely formed in Ni-Si alloys. The number density of voids was one hundredth of that of SFT observed in 473 K irradiated Ni-Cu alloys. Possible formation processes of interstitial loops, SFT dislocation lines and voids are discussed.

Damage structures in fission-neutron irradiated Ni-based alloys at high temperatures

Energy Technology Data Exchange (ETDEWEB)

Yamakawa, K.; Shimomura, Y. [Hiroshima Univ. (Japan). Faculty of Engineering

1999-01-01

The defects formed in Ni based (Ni-Si, Ni-Cu and Ni-Fe) alloys which were irradiated with fission-neutrons were examined by electron microscopy. Irradiations were carried out at 473 K and 573 K. In the 473 K irradiated specimens, a high density of large interstitial loops and small vacancy clusters with stacking fault tetrahedra (SFT) were observed. The number densities of these two types of defects did not strongly depend on the amount of solute atoms in each alloy. The density of the loops in Ni-Si alloys was much higher than those in Ni-Cu and Ni-Fe alloys, while the density of SFT only slightly depended on the kind of solute. Also, the size of the loops depended on the kinds and amounts of solute. In 573 K irradiated Ni-Cu specimens, a high density of dislocation lines developed during the growth of interstitial loops. In Ni-Si alloys, the number density and size of the interstitial loops changed as a function of the amount of solute. Voids were formed in Ni-Cu alloys but scarcely formed in Ni-Si alloys. The number density of voids was one hundredth of that of SFT observed in 473 K irradiated Ni-Cu alloys. Possible formation processes of interstitial loops, SFT, dislocation lines and voids are discussed. (orig.) 8 refs.

Formation, thermal stability and mechanical properties of bulk glassy alloys with a diameter of 20 mm in Zr-(Ti,Nb)-Al-Ni-Cu system

International Nuclear Information System (INIS)

Inoue, A.; Zhang, Q.S.; Zhang, W.; Yubuta, K.; Son, K.S.; Wang, X.M.

2009-01-01

Bulk glassy alloy rods with a diameter of 20 mm were produced for Zr 61 Ti 2 Nb 2 Al 7.5 Ni 10 Cu 17.5 and Zr 60 Ti 2 Nb 2 Al 7.5 Ni 10 Cu 18.5 by a tilt casting method. The replacement of Zr by a small amount of Ti and Nb caused a distinct increase in the maximum diameter from 16 mm for Zr 65 Al 7.5 Ni 10 Cu 17.5 to 20 mm, accompanying the decrease in liquidus temperature and the increase in reduced glass transition temperature. The primary precipitation phase from supercooled liquid also shows a distinct change, i.e., from coexistent Zr 2 Cu, Zr 2 Ni and Zr 6 NiAl 2 phases for the 65%Zr alloy to an icosahedral phase for the 61%Zr and 60%Zr alloys. These results allow us to presume that the enhancement of the glass-forming ability is due to an increase in the stability of supercooled liquid against crystallization caused by the development of icosahedral short-range ordered atomic configurations. The 60%Zr specimens taken from the central and near-surface regions in the transverse cross section at the site which is 15 mm away from the bottom surface of the cast glassy rod with a diameter of 20 mm exhibit good mechanical properties under a compressive deformation mode, i.e., Young's modulus of 81 GPa, large elastic strain of 0.02, high yield strength of 1610 MPa and distinct plastic strain of 0.012. Besides, a number of shear bands are observed along the maximum shear stress plane on the peripheral surface near the final fracture site. The finding of producing the large scale Zr-based bulk glassy alloys exhibiting reliable mechanical properties is encouraging for future advancement of bulk glassy alloys as a new type of functional material. (author)

Critical behavior of the ferromagnetic-paramagnetic phase transition in Fe{sub 90−x}Ni{sub x}Zr{sub 10} alloy ribbons

Energy Technology Data Exchange (ETDEWEB)

Thanh, Tran Dang, E-mail: thanhxraylab@yahoo.com [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Institute of Materials Science, VAST, 18 Hoang Quoc Viet, Hanoi (Viet Nam); Huy Dan, Nguyen [Institute of Materials Science, VAST, 18 Hoang Quoc Viet, Hanoi (Viet Nam); Phan, The-Long; Yu, Seong-Cho, E-mail: scyu@chungbuk.ac.kr [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Kumarakuru, Haridas; Olivier, Ezra J.; Neethling, Johannes H. [Centre for HRTEM, Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa)

2014-01-14

This work presents a detailed study on the critical behavior of the ferromagnetic-paramagnetic (FM-PM) phase transition in Fe{sub 90−x}Ni{sub x}Zr{sub 10} (x = 0 and 5) alloy ribbons. Basing on field dependences of magnetization (M-H), M{sup 2} versus H/M plots prove the alloys exhibiting a second-order magnetic phase transition. To investigate the nature of the FM-PM phase transition at T{sub C} = 245 and 306 K for x = 0 and 5, respectively, we performed a critical-exponent study. The values of critical components β, γ, and δ determined by using the modified Arrott plots, Kouvel-Fisher (KF), and critical isotherm analyses agree with each other. For x = 0, the critical parameters β = 0.365 ± 0.013 and γ = 1.615 ± 0.033 are obtained by modified Arrott plots while β = 0.368 ± 0.008 and γ = 1.612 ± 0.016 are obtained by the KF method. These values are close to those expected for the 3D-Heisenberg model, revealing short-range FM interactions in Fe{sub 90}Zr{sub 10}. Meanwhile, for x = 5, the values of the critical parameters β = 0.423 ± 0.008 and γ = 1.325 ± 0.036 are obtained by modified Arrott plots, and β = 0.425 ± 0.006 and γ = 1.323 ± 0.012 are obtained by the KF method. The falling of the β value in between the values of the mean-field theory (β = 0.5) and the 3D-Heisenberg model (β = 0.365) indicates an existence of FM short-range order and magnetic inhomogeneity in Fe{sub 85}Ni{sub 5}Zr{sub 10}. With a partial replacement of Ni for Fe in Fe{sub 90−x}Ni{sub x}Zr{sub 10}, the value of the critical exponent β trends to shift towards that of the mean-field theory. Such the result proves the presence of Ni favors establishing FM long-range order. The nature of this phenomenon is carefully discussed.

Wear behavioral study of as cast and 7 hr homogenized Al25Mg2Si2Cu4Ni alloy at constant load

Science.gov (United States)

Harlapur, M. D.; Sondur, D. G.; Akkimardi, V. G.; Mallapur, D. G.

2018-04-01

In the current study, the wear behavior of as cast and 7 hr homogenized Al25Mg2Si2Cu4Ni alloy has been investigated. Microstructure, SEM and EDS results confirm the presence of different intermetallic and their effects on wear properties of Al25Mg2Si2Cu4Ni alloy in as cast as well as aged condition. Alloying main elements like Si, Cu, Mg and Ni partly dissolve in the primary α-Al matrix and to some amount present in the form of intermetallic phases. SEM structure of as cast alloy shows blocks of Mg2Si which is at random distributed in the aluminium matrix. Precipitates of Al2Cu in the form of Chinese script are also observed. Also `Q' phase (Al-Si-Cu-Mg) be distributed uniformly into the aluminium matrix. Few coarsened platelets of Ni are seen. In case of 7 hr homogenized samples blocks of Mg2Si get rounded at the corners, Platelets of Ni get fragmented and distributed uniformly in the aluminium matrix. Results show improved volumetric wear resistance and reduced coefficient of friction after homogenizing heat treatment.

Severe plastic deformation of melt-spun shape memory Ti2NiCu and Ni2MnGa alloys

International Nuclear Information System (INIS)

Pushin, Vladimir G.; Korolev, Alexander V.; Kourov, Nikolai I.; Kuntsevich, Tatiana E.; Valiev, Eduard Z.; Yurchenko, Lyudmila I.; Valiev, Ruslan Z.; Gunderov, Dmitrii V.; Zhu, Yuntian T.

2006-01-01

This paper describes the influence of severe plastic deformation (SPD) on the structure, phase transformations, and physical properties of melt-spun Ti 2 NiCu-based and Ni 2 MnGa-based shape memory intermetallic alloys. It was found that the SPD by high pressure torsion (HPT) at room temperature can be effectively used for the synthesis of bulk nanostructured states in these initially submicro-grained or amorphized alloys obtained by melt-spinning method in the form of a ribbon. The subsequent low-temperature annealing of HPT-processed alloys leads to formation of homogeneous ultrafine nano-grained structure. This is connected with a very high degree and high homogeneity of deformation at SPD in the whole volume of deformed samples. (author)

Mechanism of abnormally slow crystal growth of CuZr alloy

International Nuclear Information System (INIS)

Yan, X. Q.; Lü, Y. J.

2015-01-01

Crystal growth of the glass-forming CuZr alloy is shown to be abnormally slow, which suggests a new method to identify the good glass-forming alloys. The crystal growth of elemental Cu, Pd and binary NiAl, CuZr alloys is systematically studied with the aid of molecular dynamics simulations. The temperature dependence of the growth velocity indicates the different growth mechanisms between the elemental and the alloy systems. The high-speed growth featuring the elemental metals is dominated by the non-activated collision between liquid-like atoms and interface, and the low-speed growth for NiAl and CuZr is determined by the diffusion across the interface. We find that, in contrast to Cu, Pd, and NiAl, a strong stress layering arisen from the density and the local order layering forms in front of the liquid-crystal interface of CuZr alloy, which causes a slow diffusion zone. The formation of the slow diffusion zone suppresses the interface moving, resulting in much small growth velocity of CuZr alloy. We provide a direct evidence of this explanation by applying the compressive stress normal to the interface. The compression is shown to boost the stress layering in CuZr significantly, correspondingly enhancing the slow diffusion zone, and eventually slowing down the crystal growth of CuZr alloy immediately. In contrast, the growth of Cu, Pd, and NiAl is increased by the compression because the low diffusion zones in them are never well developed

Growth and characterization of NixCu1-x alloy films, NixCu1-x/NiyCu1-y multilayers, and nanowires

International Nuclear Information System (INIS)

Kazeminezhad, I.

2001-12-01

It was found that it is possible to grow Ni x Cu 1-x alloy systems of arbitrary composition by electrodepositing well-defined sub-monolayer quantities of Ni and Cu in alternation using a new method based on that used previously to prepare potentiostatically deposited magnetic multilayers from a single sulphamate-based electrolyte. Following growth, the chemical composition of Ni x Cu 1-x alloy films was obtained by ZAF-corrected energy dispersive X-Ray (EDX) analysis and less than a 4% difference between the nominal and actual composition was observed. The structure of the films was investigated by high-angle X-ray diffractometry (HAXRD) and transmission electron microscopy (TEM). The films grown on polycrystalline Cu substrates had (100) texture, while those grown on Au-coated glass had (111) texture. Some evidence of Ni clustering was obtained by vibrating sample magnetometry (VSM). Self-organisation of the deposited metal was suggested for Ni potentials more positive than ∼-1.4V. The transition from a Ni/Cu multilayer to a Ni x Cu 1-x alloy was also studied and an interesting aspect, namely a plateau region in a plot of magnetisation as a function of Ni layer thickness was observed, suggesting a preferred Ni cluster size in these alloy films. Anisotropic magnetoresistance (AMR) of the films decreased with increasing Cu content at 300K and 77K. SQUID measurements for Ni 0.52 Cu 0.48 and Ni 0.62 CU 0.38 films showed that they become much more strongly ferromagnetic at low temperatures. Evidence for blocked -superparamagnetic behaviour above a blocking temperature (T B ) of the films was obtained from zero-field-cooled (ZFC) and field-cooled (FC) magnetic susceptibility measurements. Ni x Cu 1-x /Ni y Cu 1-y alloy/alloy multilayer films with short repeat distance were successfully fabricated using this method. Up to third order satellite peaks observed in HAXRD showed that the interface is sharp. Room temperature longitudinal magnetoresistance measurements showed

Calculation of Gibbs energy of Zr-Al-Ni, Zr-Al-Cu, Al-Ni-Cu and Zr-Al-Ni-Cu liquid alloys based on quasiregular solution model

International Nuclear Information System (INIS)

Li, H.Q.; Yang, Y.S.; Tong, W.H.; Wang, Z.Y.

2007-01-01

With the effects of electronic structure and atomic size being introduced, the mixing enthalpy as well as the Gibbs energy of the ternary Zr-Al-Cu, Ni-Al-Cu, Zr-Ni-Al and quaternary Zr-Al-Ni-Cu systems are calculated based on quasiregular solution model. The computed results agree well with the experimental data. The sequence of Gibbs energies of different systems is: G Zr-Al-Ni-Cu Zr-Al-Ni Zr-Al-Cu Cu-Al-Ni . To Zr-Al-Cu, Ni-Al-Cu and Zr-Ni-Al, the lowest Gibbs energy locates in the composition range of X Zr 0.39-0.61, X Al = 0.38-0.61; X Ni = 0.39-0.61, X Al = 0.38-0.60 and X Zr = 0.32-0.67, X Al = 0.32-0.66, respectively. And to the Zr-Ni-Al-Cu system with 66.67% Zr, the lowest Gibbs energy is obtained in the region of X Al = 0.63-0.80, X Ni = 0.14-0.24

To study the mechanical properties of unidirectionally and cross rolled Ni-Cu alloy produced in VIM

International Nuclear Information System (INIS)

Afzal, M.; Ajmal, M.; Butt, Z.T.

2009-01-01

Ni-Cu alloy was developed by melting in a vacuum induction furnace using pure elements i.e., Ni, Cu, Fe, Si, Mn and Cr. Four heats of approximately 4 kg each were prepared. All the heats have been casted in an ingot of 10 cm long and 5 cm in diameter in vacuum. These ingots were hot forged at a temperature of 900 deg. C to break down the cast dendritic structure. All forged plates were cut into two halve. One half was rolled in unidirectional while other was rolled in multiple directions (cross rolling). During rolling after every 25 % reduction, the cold rolled samples were annealed at a temperature of 900 deg. C for one hour. Each plate was cold rolled to a final thickness of 0.345 mm. Half of these rolled plate produced either by cross rolling or unidirectional rolling were annealed at 900 deg. C for 20 minutes. The mechanical properties of each rolled plate in cold reduction and in annealed were also measured. Unidirectional rolling and cross rolling has almost similar mechanical properties. The annealing of cross rolled and unidirectional rolling drastically reduced the yield strength. It was observed that the Ni-Cu alloy produced has slightly lower yield and ultimate tensile strength compared to the values reported in standards of Monel-400. However, it is within the acceptable range to be used for the various applications. (author)

Toxicity assessment and selective leaching characteristics of Cu-Al-Ni shape memory alloys in biomaterials applications.

Science.gov (United States)

Chang, Shih-Hang; Chen, Bor-Yann; Lin, Jin-Xiang

2016-04-06

Cu-Al-Ni shape memory alloys (SMAs) possess two-way shape memory effects, superelasticity, and damping capacity. Nonetheless, Cu-Al-Ni SMAs remain promising candidates for use in biomedical applications, as they are more economical and machinable than other SMAs. Ensuring the biocompatibility of Cu-Al-Ni SMAs is crucial to their development for biomedical applications. Therefore, this study aimed to assess the toxicity of Cu-Al-Ni SMAs using a Probit dose-response model and augmented simplex design. In this study, the effects of Cu2+, Al3+ and Ni2+ metal ions on bacteria (Escherichia coli DH5α) using Probit dose-response analysis and augmented simplex design to assess the actual toxicity of the Cu-Al-Ni SMAs. Extraction and repetition of Escherichia coli DH5α solutions with high Cu2+ ion concentrations and 30-hour incubation demonstrated that Escherichia coli DH5α was able to alter its growth mechanisms in response to toxins. Metal ions leached from Cu-Al-Ni SMAs appeared in a multitude of compositions with varying degrees of toxicity, and those appearing close to a saddle region identified in the contour plot of the augmented simplex model were identified as candidates for elevated toxicity levels. When the Cu-13.5Al-4Ni SMA plate was immersed in Ringer's solution, the selective leaching rate of Ni2+ ions far exceeded that of Cu2+ and Al3+. The number of Cu2+, Al3+ and Ni2+ ions leached from Cu-Al-Ni SMAs increased with immersion time; however, at higher ratios, toxicity interactions among the metal ions had the effect of gradually reducing overall toxicity levels with regard to Escherichia coli DH5α. The quantities of Cu2+, Al3+ and Ni2+ ions leached from the Cu-13.5Al-4Ni SMA plate increased with immersion time, the toxicity interactions associated with these compositions reduced the actual toxicity to Escherichia coli DH5α.

Study of the magnetic anisotropy in Ni/Cu and Ni/glass thin films

International Nuclear Information System (INIS)

Cherif, S.-M.; Layadi, A.; Ben Youssef, J.; Nacereddine, C.; Roussigne, Y.

2007-01-01

The magnetic properties of evaporated Ni/Cu and Ni/glass thin films have been investigated by means of the vibrating sample magnetometer (VSM), the Brillouin light scattering (BLS) and magnetic force microscopy (MFM). The Ni thickness, t, ranges from 31 to 165 nm. The second- and fourth-order magnetic anisotropy constants, K 1 and K 2 , have been included; for the Ni/Cu series, K 1 was found to decrease from 1.0x10 6 to 0.18x10 6 erg/cm 3 as t increases from 31 to 165 nm, while K 2 increased from 0.24x10 6 to 0.8x10 6 erg/cm 3 . Over all the thickness range, the magnetization easy axis is in plane. For thinner films, there is a good agreement between anisotropy constant values inferred from VSM and BLS. Stripe domains were observed for t≥165 nm in Ni/glass and t≥90 nm in Ni/Cu

Linear arrangement of nano-scale magnetic particles formed in Cu-Fe-Ni alloys

Energy Technology Data Exchange (ETDEWEB)

Kang, Sung, E-mail: k3201s@hotmail.co [Department of Materials Engineering (SEISAN), Yokohama National University, 79-5 Tokiwadai, Hodogayaku, Yokohama, 240-8501 (Japan); Takeda, Mahoto [Department of Materials Engineering (SEISAN), Yokohama National University, 79-5 Tokiwadai, Hodogayaku, Yokohama, 240-8501 (Japan); Takeguchi, Masaki [Advanced Electron Microscopy Group, National Institute for Materials Science (NIMS), Sakura 3-13, Tsukuba, 305-0047 (Japan); Bae, Dong-Sik [School of Nano and Advanced Materials Engineering, Changwon National University, Gyeongnam, 641-773 (Korea, Republic of)

2010-04-30

The structural evolution of nano-scale magnetic particles formed in Cu-Fe-Ni alloys on isothermal annealing at 878 K has been investigated by means of transmission electron microscopy (TEM), electron dispersive X-ray spectroscopy (EDS), electron energy-loss spectroscopy (EELS) and field-emission scanning electron microscopy (FE-SEM). Phase decomposition of Cu-Fe-Ni occurred after an as-quenched specimen received a short anneal, and nano-scale magnetic particles were formed randomly in the Cu-rich matrix. A striking feature that two or more nano-scale particles with a cubic shape were aligned linearly along <1,0,0> directions was observed, and the trend was more pronounced at later stages of the precipitation. Large numbers of <1,0,0> linear chains of precipitates extended in three dimensions in late stages of annealing.

Characterization of the shape memory properties of a Ni45.3Ti39.7Hf10Pd5 alloy

International Nuclear Information System (INIS)

Acar, E.; Karaca, H.E.; Tobe, H.; Noebe, R.D.; Chumlyakov, Y.I.

2013-01-01

Highlights: •Ni 45.3 Ti 39.7 Hf 10 Pd 5 alloys have transformation strain of up to 4.6% and work output of up to 29 J cm −3 . •The alloy showed good superelastic behavior at 90 °C with recoverable strain of 4.3%. •The alloy exhibited 1.6% two-way shape memory strain after a simple training procedure. •The formation of 〈0 1 1〉 type II twins in martensite plates results in large transformation strain. -- Abstract: The load-biased shape memory and superelastic responses of a Ni 45.3 Ti 39.7 Hf 10 Pd 5 polycrystalline alloy were investigated in compression. Transformation strain of up to 4.6% and work output of up to 29 J cm −3 were determined from load-biased thermal cycling experiments. The alloy showed good superelastic behavior at 90 o C with recoverable strain of over 4%. It was also determined that the Ni 45.3 Ti 39.7 Hf 10 Pd 5 alloy could develop two-way shape memory strain of 1.6% without an intense training process. Transmission electron microscopy (TEM) revealed that the internal twins formed in the martensite variants were 〈0 1 1〉 type II twins

Precipitation kinetics in binary Fe–Cu and ternary Fe–Cu–Ni alloys via kMC method

Directory of Open Access Journals (Sweden)

Yi Wang

2017-08-01

Full Text Available The precipitation kinetics of coherent Cu rich precipitates (CRPs in binary Fe–Cu and ternary Fe–Cu–Ni alloys during thermal aging was modelled by the kinetic Monte Carlo method (kMC. A good agreement of the precipitation kinetics of Fe–Cu was found between the simulation and experimental results, as observed by means of advancement factor and cluster number density. This agreement was obtained owing to the correct description of the fast cluster mobility. The simulation results indicate that the effects of Ni are two-fold: Ni promotes the nucleation of Cu clusters; while the precipitation kinetics appears to be delayed by Ni addition during the coarsening stage. The apparent delayed precipitation kinetics is revealed to be related with the cluster mobility, which are reduced by Ni addition. The reduction effect of the cluster mobility weakens when the CRPs sizes increase. The results provide a view angle on the effects of solute elements upon Cu precipitation kinetics through the consideration of the non-conventional cluster growth mechanism, and kMC is verified to be a powerful approach on that.

Topological model of austenite-martensite interfaces in Cu-Al-Ni alloy

Czech Academy of Sciences Publication Activity Database

Ostapovets, Andriy; Zárubová, Niva; Paidar, Václav

2012-01-01

Roč. 122, č. 3 (2012), s. 493-496 ISSN 0587-4246. [International Symposium on Physics of Materials, ISPMA /12./. Praha, 04.09.2011-08.09.2011] R&D Projects: GA AV ČR IAA100100920 Institutional research plan: CEZ:AV0Z10100520 Keywords : CuAlNi * alloy * experimental data * in-situ * topological models * transmission electron microscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.531, year: 2012

Features of Crystallization of Rapidly Quenched Ni45Ti32Hf18Cu5 and Ni25Ti32Hf18Cu25 Alloys from Melt with High-Temperature Shape Memory Effect

Science.gov (United States)

Pushin, A. V.; Pushin, V. G.; Kuntsevich, T. E.; Kuranova, N. N.; Makarov, V. V.; Uksusnikov, A. N.; Kourov, N. I.

2017-12-01

A comparative study of the structure and the chemical and phase composition of Ni45Ti32Hf18Cu5 and Ni25Ti32Hf18Cu25 amorphous alloys obtained by fast-quenching of melt stream by spinning has been carried out by transmission and scanning electron microscopy and X-ray diffraction. The critical temperatures of their devitrification were determined by the data of temperatures measurements of electrical resistance. The features of the formation of ultrafine structure and the phase transformation at the vitrification depending on the regimes of heat treatment and chemical composition of alloy have been established.

Effect of surface shear on cube texture formation in heavy cold-rolled Cu-45 at%Ni alloy substrates

DEFF Research Database (Denmark)

Tian, Hui; Suo, Hongli; Liang, Yaru

2015-01-01

Two types of Cu-45 at%Ni alloy thin tapes with and without surface shear were obtained by different heavy cold rolling processes. The deformation and recrystallization textures of the two tapes were thoroughly investigated by electron back scattering diffraction technique. The results showed...... that a shear texture mainly covered the surface of the heavy deformed tapes because of the fraction between the surface of rolling mills and the thin tapes when the rolling force strongly reduced at high strain, which significantly reduced the fraction of rolling texture on the surface of the Cu-45at %Ni alloy...

FABRICATION OF Cu-Al-Ni SHAPE MEMORY THIN FILM BY THERMAL EVOPRATION

OpenAIRE

Özkul, İskender; Canbay, Canan Aksu; Tekataş, Ayşe

2017-01-01

Among the functional, materials shape memory alloysare important because of their unique properties. So, these materials haveattracted more attention to be used in micro/nano electronic andelectromechanic systems. In this work, thermal evaporation method has been usedto produce CuAlNi shape memory alloy thin film. The produced CuAlNi thin filmhas been characterized and the presence of the martensite phase wasinvestigated and compared with the CuAlNi alloy sample. CuAlNi shape memoryalloy thin...

Brazing of zirconia to titanium using Ag-Cu and Au-Ni filler alloys

Directory of Open Access Journals (Sweden)

Jean S. Pimenta

2013-12-01

Full Text Available Advanced ceramic is usually joined to metal by the well-known direct brazing process, where costly active filler alloys can be considered a limitation. Brazing using active-metal-free filler alloy as insert between the joint components is an attempt to overcome it. The active metal diffusion from the titanium member through the bulk of molten filler to the ceramic was responsible to produce an active filler alloy in loco and promote reduction of the zirconium oxide to improve wetting on the ceramic surface. Unalloyed titanium was joined in a high-vacuum furnace (<3x10-5 mbar to yttria-tetragonal zirconia polycristals (Y-TZP and zirconia partially stabilized with magnesia (Mg-PSZ, where commercial fillers Ag-28Cu and Au-18Ni with respective thermal cycles were evaluated. Helium gas leak detection test was performed at the ceramic/metal interface at room temperature; samples from reliable vacuum tight joints were examined by microstructural analysis techniques and energy dispersive X-ray analysis at the joint cross-section. Tight joints were produced with eutectic Ag-Cu filler, revealing an intermetallic layer and a dark reaction layer near the ceramic surface; titanium diffusion was efficient for superficial chemical interactions between individual components. Brazing joints were also tested using three-point flexure testing.

Internal carbonitriding behavior of Ni-V, Ni-Cr, and Ni-3Nb alloys

International Nuclear Information System (INIS)

Allen, A.T.; Douglass, D.L.

1999-01-01

Ni-2V, Ni-5V, Ni-12V, Ni-10Cr, Ni-20Cr, and Ni-3Nb alloys were carbonitrided in C 3 H 6 and NH 3 gas mixtures (bal H 2 ) over the range 700--1,000 C. Carbonitridation of Ni-12V and Ni-20Cr in C 3 H 6 /NH 3 /H 2 (1.5/1.5/97 v/o) and (1.5/10/88.5 v/o) produced duplex subscales consisting of near-surface nitrides with underlying carbides. Growth of each zone obeyed the parabolic rate law under most conditions. The presence of carbon generally did not effect the depth of the nitride zones compared to nitriding the alloys in NH 3 /H 2 (10/90 v/o). However, at 700 C, the nitride zones were deeper in the carbonitrided Ni-V alloys and Ni-20Cr. The presence of nitrogen generally increased the depth of the carbide zones in Ni-12V and Ni-20Cr compared to carburizing these alloys in C 3 H 6 /H 2 (1.5/98.5 v/o). VN, CrN, and NbN formed in Ni-V, Ni-Cr, and Ni-Nb alloys, respectively, whereas the underlying carbide layers contained V 4 C 3 in Ni-12V, Cr 3 C 2 above a zone of Cr 7 C 3 in Ni-20Cr, and NbC in Ni-3Nb. The solubilities and diffusivities of nitrogen and carbon in nickel were determined. Nitrogen and carbon each exhibited retrograde solubility with temperature in pure Ni in both carbonitriding environments. Nitrogen diffusion in nickel was generally lower in each carbonitriding mixture compared to nitrogen diffusion in a nitriding environment, except at 700 C when nitrogen diffusion was higher. Carbon diffusion in nickel was generally higher in the carbonitriding environments compared to carbon diffusion in a carburizing environment

Microstructural evolution in decomposition of amorphous Zr41Ti14Cu12.5Ni10Be22.5 alloy, as investigated by small-angle neutron scattering

International Nuclear Information System (INIS)

Liu Junming; Hahn-Meitner-Inst. Berlin, Bereich, NM; Nanjing Univ.

1997-01-01

Small angle neutron scattering (SANS) has been applied to investigate decomposition kinetics and microstructural evolution in amorphous Zr 41 Ti 14 Cu 12.5 Ni 10 Be 22.5 . It is detected that immediately after the alloy is submitted into the supercooled liquid range, phase separation develops rapidly in the early stage, leaving a sluggish coarsening stage. The decomposed alloy finally achieves a roughly regular microstructure which consists of one particle-like supercooled liquid phase embedded in the similarly disordered matrix. The morphology of the particles as a function of time is evaluated, predicting a bar-like pattern. Strong temperature dependence of the phase separation is observed. (orig.)

EVALUATION OF MACHINABILITY OF DUCTILE IRONS ALLOYED WITH Ni AND Cu IN TERMS OF CUTTING FORCES AND SURFACE QUALITY

Directory of Open Access Journals (Sweden)

Yücel AŞKUN

2003-02-01

Full Text Available Due to the enhanced strength, ductility and thoughness of Ductile Iron (DI when compared to the other types cast iron, its machinability is relatively poor. When a steel part is replaced with ductile iron, however, better machinability is considered to be the most important gain. This study presents the results of machining tests of ductile irons alloyed with Ni and Cu at various contents to determine the effect of their microstructure and mechanical properties on cutting forces and surface roughness. Six different specimen groups of ductile iron alloyed with various amounts of nickel and copper were subjected to machining tests and their machinabilities were investigated based on cutting forces and surface roughness criteria. The results were evaluated according to microstructure and mechanical properties of specimens determined before. In terms of both criterion, the best result obtained was specimen added 0.7 % Ni and 0.7 % Cu. When the specimens were evaluated according to their mechanical properties, the specimens alloyed 1 % Ni and 0.65 % Cu seemed promising.

Soft magnetic properties of hybrid ferromagnetic films with CoFe, NiFe, and NiFeCuMo layers

Energy Technology Data Exchange (ETDEWEB)

Choi, Jong-Gu [Eastern-western Biomedical Engineering, Sangji University, Wonju 220-702 (Korea, Republic of); Hwang, Do-Guwn [Dept. of Oriental Biomedical Engineering, Sangji University, Wonju 220-702 (Korea, Republic of); Rhee, Jang-Roh [Dept. of Physics, Sookmyung Women' s University, Seoul 140-742 (Korea, Republic of); Lee, Sang-Suk, E-mail: sslee@sangji.ac.kr [Dept. of Oriental Biomedical Engineering, Sangji University, Wonju 220-702 (Korea, Republic of)

2011-09-30

Two-layered ferromagnetic alloy films (NiFe and CoFe) with intermediate NiFeCuMo soft magnetic layers of different thicknesses were investigated to understand the relationship between coercivity and magnetization process by taking into account the strength of hard-axis saturation field. The thickness dependence of H{sub EC} (easy-axis coercivity), H{sub HS} (hard-axis saturation field), and {chi} (susceptibility) of the NiFeCuMo thin films in glass/Ta(5 nm)/[CoFe or NiFe(5 nm-t/2)]/NiFeCuMo(t = 0, 4, 6, 8, 10 nm)/[CoFe or NiFe(5 nm-t/2)]/Ta(5 nm) films prepared using the ion beam deposition method was determined. The magnetic properties (H{sub EC}, H{sub HS}, and {chi}) of the ferromagnetic CoFe, NiFe three-layers with an intermediate NiFeCuMo super-soft magnetic layer were strongly dependent on the thickness of the NiFeCuMo layer.

Study of the magnetic anisotropy in Ni/Cu and Ni/glass thin films

Energy Technology Data Exchange (ETDEWEB)

Cherif, S.-M. [Laboratoire PMTM, Institut Galilee, Univeriste Paris 13, Villetaneuse, 93340 (France); Layadi, A. [Departement de Physique, Universite Ferhat Abbas, Setif 19000 (Algeria)]. E-mail: a_layadi@yahoo.fr; Ben Youssef, J. [Laboratoire de Magnetisme de Bretagne, U.B.O., Brest 29238 (France); Nacereddine, C. [Departement de Physique, Universite Ferhat Abbas, Setif 19000 (Algeria); Roussigne, Y. [Laboratoire PMTM, Institut Galilee, Univeriste Paris 13, Villetaneuse, 93340 (France)

2007-01-01

The magnetic properties of evaporated Ni/Cu and Ni/glass thin films have been investigated by means of the vibrating sample magnetometer (VSM), the Brillouin light scattering (BLS) and magnetic force microscopy (MFM). The Ni thickness, t, ranges from 31 to 165 nm. The second- and fourth-order magnetic anisotropy constants, K {sub 1} and K {sub 2}, have been included; for the Ni/Cu series, K {sub 1} was found to decrease from 1.0x10{sup 6} to 0.18x10{sup 6} erg/cm{sup 3} as t increases from 31 to 165 nm, while K {sub 2} increased from 0.24x10{sup 6} to 0.8x10{sup 6} erg/cm{sup 3}. Over all the thickness range, the magnetization easy axis is in plane. For thinner films, there is a good agreement between anisotropy constant values inferred from VSM and BLS. Stripe domains were observed for t{>=}165 nm in Ni/glass and t{>=}90 nm in Ni/Cu.

Microstructure and Mechanical Characterization of a Dissimilar Friction-Stir-Welded CuCrZr/CuNiCrSi Butt Joint

Directory of Open Access Journals (Sweden)

Youqing Sun

2018-05-01

Full Text Available Dissimilar CuNiCrSi and CuCrZr butt joints were successfully frictionstirwelded at constant welding speed of 150 mm/min and rotational speed of 1400 rpm with the CuCrZr alloy or the CuNiCrSi alloy located on the advancing side (AS. The microstructure and mechanical properties of joints were investigated. When the CuCrZr alloy was located on the AS, the area of retreating material in the nugget zone was a little bigger. The Cr solute-rich particles were found in the nugget zone on CuCrZr side (CuCrZr-NZ while a larger density of solute-rich particles identified as the concentration of Cr and Si element was found in the nugget zone on CuNiCrSi side (CuNiCrSi-NZ. The Cr precipitates and δ-Ni2Si precipitates were found in the base metal on CuNiCrSi side (CuNiCrSi-BM but only Cr precipitates can be observed in the base metal on CuCrZr side (CuCrZr-BM. Precipitates were totally dissolved into Cu matrix in both CuCrZr-NZ and CuNiCrSi-NZ, which led to a sharp decrease in both micro-hardness and tensile strength from BM to NZ. When the CuNiCrSi was located on the AS, the tensile testing results showed the fracture occurred at the CuCrZr-NZ, while the fracture was found at the mixed zone of CuNiCrSi-NZ and CuCrZr-NZ for the other case.

Cu-Al-Ni Shape Memory Single Crystal Wires with High Transformation Temperature

Science.gov (United States)

Hautcoeur, Alain; Fouché, Florian; Sicre, Jacques

2016-01-01

CN-250X is a new material with higher performance than Nickel-Titanium Shape Memory Alloy (SMA). For space mechanisms, the main disadvantage of Nickel-Titanium Shape Memory Alloy is the limited transformation temperature. The new CN-250X Nimesis alloy is a Cu-Al-Ni single crystal wire available in large quantity because of a new industrial process. The triggering of actuators made with this Cu-Al-Ni single crystal wire can range from ambient temperature to 200 C in cycling and even to 250 C in one-shot mode. Another advantage of CN-250X is a better shape recovery (8 to 10%) than Ni-Ti (6 to 7%). Nimesis is the first company able to produce this type of material with its new special industrial process. A characterization study is presented in this work, including the two main solicitation modes for this material: tensile and torsion. Different tests measure the shape recovery of Cu-Al-Ni single crystals wires during heating from room temperature to a temperature higher than temperature of end of martensitic transformation.

Electrochemical properties of the ball-milled LaMg10NiMn alloy with Ni powders

International Nuclear Information System (INIS)

Wang Yi; Wang Xin; Gao Xueping; Shen Panwen

2008-01-01

The electrochemical characteristics of the ball-milled LaMg 10 NiMn alloys with Ni powders were investigated. It was found that the ball-milled LaMg 10 NiMn + 150 wt.% Ni composite exhibited higher first discharge capacity and better cycle performance. By means of the analysis of electrochemical impedance spectra (EIS), it was shown that the existence of manganese in LaMg 10 NiMn alloy increased the electrocatalytic activity due to its catalytic effect, and destabilized metal hydrides, and so reduced the hydrogen diffusion resistance. These contributed to the higher discharge capacity of the ball-milled LaMg 10 NiMn-Ni composite. According to the analytical results of X-ray diffraction (XRD), EIS and steady-state polarization (SSP) experiments, the inhibition of metal corrosion is not the main reason for the better cycle performance. The main reason is that the electrochemical reaction resistance of the ball-milled LaMg 10 NiMn-Ni composite is always lower than that of the ball-milled LaMg 10 Ni 2 -Ni composite because the former one contains manganese, which is a catalyst for the electrode reaction

Some aspects of thermally induced martensite in Fe-30% Ni-5% Cu alloy

International Nuclear Information System (INIS)

Guener, M.; Gueler, E.; Yasar, E.; Aktas, H.

2007-01-01

Kinetical, morphological, crystallographical and several thermal properties of thermally induced martensite in the austenite phase of Fe-30% Ni-5% Cu alloy were investigated. Scanning electron microscope (SEM), transmission electron microscope (TEM) and differential scanning calorimetry (DSC) techniques were used during study. Kinetics of the transformation was found to be as athermal type. SEM and TEM observations revealed α' (BCC) martensite formation in the austenite phase of alloy by thermal effect. These thermally induced α' martensites exhibited a thin plate-like morphology with twinnings

Paduan Ni-Cu-Mn Sebagai Logam Alternatif Kedokteran Gigi: Efek Perendaman dalam Larutan 0,1% Sodium Sulfida

Directory of Open Access Journals (Sweden)

Bambang Irawan

2015-09-01

Full Text Available In this study, the ternary base alloys of nickel-copper-manganese (Ni-Cu-Mn alloys are prepared and these ternary alloys systems, which were constituted from higher nickel and lower copper contents than copper-base alloy ones, were evaluated by a tarnish test. Tarnish tests conducted in a 0,1% sodium sulphide solution (pH=12 at 37◦C. All test specimens were case into square paddles of 15 mm x 20 mm x 2,5 mm using the lost-wax technique with a phosphate-bonded investment. The surface of the specimens were then prepared with abrasion papers down to a 600 grit finish. Tarnish attack was quantitatively evaluated by Fibre colorimetry. The results of tarnish test showed that ternary nickel-copper-manganese alloys, such as 40Ni-30Cu-30Mn and 50Ni-30Cu-20Mn, have superior tarnishment resistance than other alloys, e.g. 20Ni-40Cu-40Mn, 30Ni-30Cu-40Mn and 30Ni-40Cu-30Mn. It was also found that 40Ni-30Cu-30Mn and 50Ni-30Cu-20Mn alloys have lower values of colour change vector than the other alloys given above.

Pengaruh Penambahan Ni, Cu, dan Al dan Waktu Milling pada Mechanical Alloying Terhadap Sifat Absorpsi dan Desorpsi Mg sebagai Material Penyimpan Hidrogen

Directory of Open Access Journals (Sweden)

Febrian Budi Pratama

2012-09-01

Full Text Available Mg merupakan salah satu material yang digunakan sebagai material penyimpan hidrogen dengan membentuk MgH2. Sifat absorpsi dan desorpsi hidrogen dari suatu metal hidrida salah satunya tergantung  pada bahan, unsur penambah, dan metode pembuatannya. Pada penelitian kali ini Mg sebagai material penyimpan hidrogen dihasilkan melalui metode mechanical alloying dengan unsur penambah Ni, Cu, dan Al dan variasi waktu milling 10, 20, 30 jam. Selanjutnya sampel dilakukan pengujian SEM, XRD, DSC, dan Uji hidrogenisasi. Dari data uji diperoleh bahwa meningkatnya waktu milling menurunkan ukuran partikel sehingga meningkatkan wt% hidrogen terabsorb dan menurunkan temperatur onset desorpsi. Namun efek aglomerasi dan coldwelding yang berlebih pada proses mechanical alloying mengakibatkan ukuran partikel menjadi lebih besar. Unsur pemadu Al dan Cu berfungsi sebagai katalis, sedangkan Ni berfungsi sebagai pemadu yang ikut bereaksi dengan hidrogen. Mg10wt%Al dengan waktu milling 20 jam mempunyai nilai weight percent terbaik H2 yaitu 0.38% dalam temperatur hidrogenisasi 2500C, tekanan 3 atm, dan waktu tahan 1 jam. Sedangkan Mg10wt%Al dengan waktu milling 30 jam memiliki temperatur onset paling rendah yaitu 341.490C Kata Kunci— Absorpsi, Desorpsi, Material Penyimpan Hidrogen, Mechanical Alloying, Mg

Long-term superelastic cycling at nano-scale in Cu-Al-Ni shape memory alloy micropillars

Energy Technology Data Exchange (ETDEWEB)

San Juan, J., E-mail: jose.sanjuan@ehu.es; Gómez-Cortés, J. F. [Dpto. Física Materia Condensada, Facultad de Ciencia y Tecnología, Univ. del País Vasco UPV/EHU, Apdo. 644, 48080 Bilbao (Spain); López, G. A.; Nó, M. L. [Dpto. Física Aplicada II, Facultad de Ciencia y Tecnología, Univ. del País Vasco UPV/EHU, Apdo. 644, 48080 Bilbao (Spain); Jiao, C. [FEI, Achtseweg Noord 5, 5651 GG Eindhoven (Netherlands)

2014-01-06

Superelastic behavior at nano-scale has been studied along cycling in Cu-Al-Ni shape memory alloy micropillars. Arrays of square micropillars were produced by focused ion beam milling, on slides of [001] oriented Cu-Al-Ni single crystals. Superelastic behavior of micropillars, due to the stress-induced martensitic transformation, has been studied by nano-compression tests during thousand cycles, and its evolution has been followed along cycling. Each pillar has undergone more than thousand cycles without any detrimental evolution. Moreover, we demonstrate that after thousand cycles they exhibit a perfectly reproducible and completely recoverable superelastic behavior.

Characterization of a hot-rolled Cu--Al--Ni--Ti shape memory alloy

International Nuclear Information System (INIS)

Segui, C.; Pons, J.; Cesari, E.

1999-01-01

The changes in the martensitic transformation of a Cu-Al-Ni-Ti alloy hot-rolled at different temperatures have been studied in detail, covering different aspects such as ageing in the parent phase at temperatures ranging between 250 and 350 o C, stabilisation of the martensite and betatization of the previously hot-rolled specimens. Besides the evolution of transformation temperatures upon different thermal treatments, special attention has been paid to the changes in mechanical properties of the alloy, such as elastic modulus and internal friction. These results are analysed in relation to the microstructural changes as observed by transmission electron microscopy. (orig.)

Experimental investigation of phase equilibria in the Zr-Cu-Ni ternary system

International Nuclear Information System (INIS)

Yang, Mujin; Wang, Cuiping; Yang, Shuiyuan; Shi, Zhan; Han, Jiajia; Liu, Xingjun

2017-01-01

The phase equilibria in the Zr-Cu-Ni ternary system are investigated combined with X-ray diffraction, electron probe micro-analysis and differential scanning calorimetry. Two isothermal sections of the Zr-Cu-Ni ternary system at 1 000 C and 1 100 C are experimentally established. Most of the binary intermetallic compounds, e.g. Zr 7 Ni 10 , ZrNi, ZrNi 5 , Zr 14 Cu 51 , and Zr 2 Cu 9 , show a remarkable ternary solubility. A new ternary compound named τ 3 (Zr 31.1-30.7 . Cu 28.5-40.3 Ni 40.4-29.0 ) is detected at 1 000 C and dissolved at 1 020 C because the nearby large liquid phase field further expands. The newly determined phase equilibria will provide important information for both thermodynamic assessment and alloy design of Zr-based metallic glass.

Local atomic and crystal structure rearrangement during the martensitic transformation in Ti50Ni25Cu25 shape memory alloy

International Nuclear Information System (INIS)

Menushenkov, Alexey; Grishina, Olga; Shelyakov, Alexander; Yaroslavtsev, Alexander; Zubavichus, Yan; Veligzhanin, Alexey; Bednarcik, Jozef; Chernikov, Roman; Sitnikov, Nikolay

2014-01-01

Highlights: • Local crystalline structure of TiNiCu SMA is investigated using EXAFS. • Peculiarities of Ni and Cu local environment are found. • Ti atoms show greater mobility relative to Ni atoms. • Ni local environment change is significant for shape memory effect. -- Abstract: The changes of crystal structure and local crystalline environment of Ti, Ni and Cu atoms in Ti 50 Ni 25 Cu 25 shape memory alloy are investigated using X-ray diffraction and extended X-ray absorption fine structure spectroscopy (EXAFS) in temperature range of martensite transformation. The analysis of the EXAFS-spectra shows that the bonds involving Ni atoms have the highest degree of disorder and the change in the local environment around Ni atoms is significant for the occurrence of the shape memory effect, while Cu atoms occupy the normal positions in the crystallographic structure and have the lowest displacement amplitude leading to the stabilization of both phases

Study on glass formation and crystallization of Zr54.5Cu20Al10Ni8Ti75 alloy

International Nuclear Information System (INIS)

Neogy, S.; Tewari, R.; Srivastava, D.; Dey, G.K.; Banerjee, S.; Vaibhaw, K.

2009-01-01

The microstructure of Zr 54.5 Cu 20 Al 10 Ni 8 Ti 75 alloy has been examined after solidification involving three different techniques viz., copper mould casting, suction casting and melt spinning. The bulk glass microstructure of the alloy obtained through copper mould casting was found to comprise of big cube Zr 2 Ni phase in a dendritic morphology and tetragonal Zr 2 Ni phase in a faulted morphology besides the amorphous phase. High-resolution electron microscopy (HREM) was carried out to examine the internal structure and interface structure of the phases. The dendritic phase was found to consist of primary and secondary dendrite arms with faceted as well rounded interfaces with the amorphous phase. Ledges were noticed at either of the interfaces with higher density at the rounded interfaces. The presence of the faulted phase was noticed in between dendritic arms. The faulted phase was found to consist of different domains corresponding to different orientations. A variety of interfaces could be noticed between these individual domains and also within a single domain itself. At least three different kinds of faulted region were identified to coexist in a single domain. The melt spun ribbon and bulk glass made through suction casting was found to be fully amorphous. The amorphous phase obtained from the three different techniques showed different degrees of medium range order as revealed by the fluctuation microscopy technique. Crystallization behavior of as solidified structures has been examined by comparing the crystallization kinetics and microstructure. Crystallization led to the transformation of the amorphous phase to nanocrystals in all the cases. The crystallization event was found to be singular in the case of copper mold cast bulk glass and multiple in the case of suction cast bulk glass and ribbon. The phase forming on crystallization was found to be the same faulted tetragonal Zr 2 Ni that was encountered during solidification. Multiple domains

Microscopy modifications in an aged Cu-Al-Ni-Mn alloy

International Nuclear Information System (INIS)

Gama, J.L.L.; Ferreira, R.A.S.

2010-01-01

An Cu-12Al-4Ni-3Mn shape memory alloy have been manufactured using an induction furnace of 24 KVA. After melting, chemical analyse was performed by X-ray fluorescence (XRF). The phase transformation of this alloy was studied in the different sequences produced during thermomechanic treatments. After homogenization, the ingot was solution treated at 850 deg C. At 750 deg C samples were submitted to a reduction by rolling to about 30% in thickness, followed by water quenching. In sequence, the ingot was cold-rolled at different thicknesses. In deformed state, sample of this alloy was submitted to the thermal analyse-DTA for identification of the phase transformation domains. For each identified domain, ageing was carried out, at different times, to evaluate the presence of the different phases. Samples were characterized ray-X diffraction. The results showed that the microstructural evolutions are of a complex nature. At 425 deg C temperature both recrystallization and precipitation of different phases were simultaneously observed. (author)

Martensitic transformation and shape memory effect in polycomponent TiNi-based alloys

International Nuclear Information System (INIS)

Khachin, V.N.; Voronin, V.P.; Sivokha, V.P.; Pushin, V.G.

1995-01-01

The results of martesitic transformation (MT) and shape memory effect (SME) in quaternary Ti 50 (NiCoCu) 50 , Ti 50 (NiFeCu) 50 and (TiAl) 50 (NiCu) 50 alloys studies are generalized in this paper. On alloying TiNi simultaneously by two elements, their individual effect on MT and SME is conserved. Martensitic transformations B2→R and B2→B19' are almost simultaneously realizing in a binary TiNi. One can selectively control each of two MT channels by selecting property of alloying elements. As a result, the alloys having any sequences of MT and their realizations temperatures, including simultaneous realization of two MTs at low temperatures, which was not observed earlier, can be produced. (orig.)

Zr-Cu-Ni-Al bulk metallic glasses with superhigh glass-forming ability

International Nuclear Information System (INIS)

Sun, Y.J.; Qu, D.D.; Huang, Y.J.; Liss, K.-D.; Wei, X.S.; Xing, D.W.; Shen, J.

2009-01-01

Zr-Cu-Ni-Al quaternary amorphous alloy compositions with varying glass-forming ability are developed by an efficient method of proportional mixing of binary eutectics. The critical diameter of the glassy sample is improved from 6 mm for Zr 53 Cu 18.7 Ni 12 Al 16.3 to 14 mm for Zr 50.7 Cu 28 Ni 9 Al 12.3 by straightforwardly adjusting the eutectic unit's coefficients. The drastic improvement in GFA is attributed to balancing the chemical affinities of the Zr, Cu, Ni and Al components in the melt prior to solidification which makes the precipitation of competing crystalline phases more difficult. As the glass-forming ability increases, the concentration of Cu in the alloys exhibits a same trend. Based on synchrotron radiation high-energy X-ray diffraction analysis and Miracle's structural model, it is envisioned that the substitution of additional Cu atoms for Zr atoms in the investigated alloys stabilizes the efficient cluster packing structure of the amorphous alloys, leading to the pronounced increase in their glass-forming ability

Effect of titanium on structure and martensitic transformation in rapidly solidified Cu-Al-Ni-Mn-Ti alloys

International Nuclear Information System (INIS)

Dutkiewicz, J.; Czeppe, T.; Morgiel, J.

1999-01-01

Alloys of composition Cu-(11.8-13.5)%Al-(3.2-4)%Ni-(2-3)%Mn and 0-1%Ti (wt.%) were cast using the melt spinning method in He atmosphere. Ribbons obtained in this process showed grains from 0.5 to 30 μm depending on the type of alloy and wheel speed. Bulk alloys and most of the ribbons contained mixed 18R and 2H type martensite at room temperature (RT). Some ribbons, crystallizing at the highest cooling rate, retained also β phase due to a drop of M s below RT. The M s temperatures in ribbons were strongly lowered with increasing wheel speed controlling the solidification rate. This drop of M s shows a linear relationship with d -1/2 , where d is grain size. The strongest decrease of M s and smallest grains were found in the ribbons containing titanium due to its grain refinement effect. The cubic Ti rich precipitates, present in both Cu-Al-Ni-Ti and Cu-Al-Ni-Mn-Ti bulk, were dispersed in ribbons cast with intermediate cooling rates of up to 26 m s -1 , but suppressed for higher cooling rates. The transformation hysteresis loop was much broader in ribbons due to presence of coherent Ti rich precipitates and differences in grain size which is particularly important in the ultra small grain size range. (orig.)

Effect of cobalt on microstructure and properties of AlCr1.5CuFeNi2Cox high-entropy alloys

Science.gov (United States)

Kukshal, Vikas; Patnaik, Amar; Bhat, I. K.

2018-04-01

The present paper investigates the effect of Co addition on the alloying behaviour, microstructure and the resulting properties of cast AlCr1.5CuFeNi2Cox high-entropy alloys intended to be used for high temperature applications. The elements Al, Cr, Cu, Fe, Ni and Co (Purity > 99) weighing approximately 800 g was melted in a high temperature vacuum induction furnace. The microstructure, phase transformation, density, microhardness and compressive strength of the samples were analysed using x-ray diffraction (XRD), scanning electron microscopes (SEM), Vickers microhardness tester and universal Testing machine. The crystalline structure of the alloys exhibits simple FCC and BCC phases. The microstructures investigation of the alloys shows the segregation of copper in the interdendritic region resulting in Cu-rich FCC phase. The addition of Co further enhances the formation of FCC phase resulting in the decrease in micro hardness value of the alloys, which varies from 471 HV to 364 HV with increase in the cobalt content from x = 0 to x = 1 (molar ratio). The similar decreasing trend is also observed for the compressive strength of the alloys.

Co-reduction of Copper Smelting Slag and Nickel Laterite to Prepare Fe-Ni-Cu Alloy for Weathering Steel

Science.gov (United States)

Guo, Zhengqi; Pan, Jian; Zhu, Deqing; Zhang, Feng

2018-02-01

In this study, a new technique was proposed for the economical and environmentally friendly recovery of valuable metals from copper smelting slag while simultaneously upgrading nickel laterite through a co-reduction followed by wet magnetic separation process. Copper slag with a high FeO content can decrease the liquidus temperature of the SiO2-Al2O3-CaO-MgO system and facilitate formation of liquid phase in a co-reduction process with nickel laterite, which is beneficial for metallic particle growth. As a result, the recovery of Ni, Cu, and Fe was notably increased. A crude Fe-Ni-Cu alloy with 2.5% Ni, 1.1% Cu, and 87.9% Fe was produced, which can replace part of scrap steel, electrolytic copper, and nickel as the burden in the production of weathering steel by an electric arc furnace. The study further found that an appropriate proportion of copper slag and nickel laterite in the mixture is essential to enhance the reduction, acquire appropriate amounts of the liquid phase, and improve the growth of the metallic alloy grains. As a result, the liberation of alloy particles in the grinding process was effectively promoted and the metal recovery was increased significantly in the subsequent magnetic separation process.

Influence of preparation method on supported Cu-Ni alloys and their catalytic properties in high pressure CO hydrogenation

DEFF Research Database (Denmark)

Wu, Qiongxiao; Eriksen, Winnie L.; Duchstein, Linus Daniel Leonhard

2014-01-01

(50 bar CO and 50 bar H2). These alloy catalysts are highly selective (more than 99 mol%) and active for methanol synthesis; however, loss of Ni caused by nickel carbonyl formation is found to be a serious issue. The Ni carbonyl formation should be considered, if Ni-containing catalysts (even...... high surface area silica supported catalysts (BET surface area up to 322 m2 g-1, and metal area calculated from X-ray diffraction particle size up to 29 m2 g-1). The formation of bimetallic Cu-Ni alloy nanoparticles has been studied during reduction using in situ X-ray diffraction. Compared...

NiTiCu/AlN/NiTiCu shape memory thin film heterostructures for vibration damping in MEMS

Energy Technology Data Exchange (ETDEWEB)

Kaur, Navjot; Kaur, Davinder, E-mail: dkaurfph@iitr.ernet.in

2014-03-25

Highlights: • Fabrication of NiTiCu/AlN/NiTiCu heterostructure using dc/rf magnetron sputtering. • Exhibits highest hardness (38 GPa) and elastic modulus (187 GPa). • Enhanced dissipation of mechanical energy (E{sub d} = 5.7 N J). • High damping capacity (0.052) and figure of merit (∼0.62). • Can be applied for vibration damping in MEMS. -- Abstract: Shape memory alloy (NiTiCu) thin films coupled with piezoelectric AlN layer produce an intelligent material for vibration damping. In the present study pure NiTiCu, NiTiCu/AlN and NiTiCu/AlN/NiTiCu heterostructures have been deposited on Si substrate using magnetron sputtering technique. By the use of the interfaces and shape memory effect provided by NiTiCu layers, the damping capacity can be increased along with increase in stiffness and mechanical hardness. The heterostructures were characterized in terms of structural, electrical, morphological and mechanical properties by X-ray diffraction (XRD), four probe resistivity method, atomic force microscopy, field emission scanning electron microscopy, and nanoindentation. The NiTiCu/AlN/NiTiCu heterostructure exhibit enhanced mechanical and damping properties as compared to NiTiCu/AlN and pure NiTiCu. This enhancement in hardness and damping of the heterostructure could be attributed to the shape memory effect of NiTiCu, intrinsic piezoelectricity of AlN and increased number of interfaces in heterostructure that help in dissipation of mechanical vibrations. The findings of this work provide additional impetus for the application of these heterostructures in emerging fields of nanotechnology and microelectro mechanical (MEMS) devices.

NiTiCu/AlN/NiTiCu shape memory thin film heterostructures for vibration damping in MEMS

International Nuclear Information System (INIS)

Kaur, Navjot; Kaur, Davinder

2014-01-01

Highlights: • Fabrication of NiTiCu/AlN/NiTiCu heterostructure using dc/rf magnetron sputtering. • Exhibits highest hardness (38 GPa) and elastic modulus (187 GPa). • Enhanced dissipation of mechanical energy (E d = 5.7 N J). • High damping capacity (0.052) and figure of merit (∼0.62). • Can be applied for vibration damping in MEMS. -- Abstract: Shape memory alloy (NiTiCu) thin films coupled with piezoelectric AlN layer produce an intelligent material for vibration damping. In the present study pure NiTiCu, NiTiCu/AlN and NiTiCu/AlN/NiTiCu heterostructures have been deposited on Si substrate using magnetron sputtering technique. By the use of the interfaces and shape memory effect provided by NiTiCu layers, the damping capacity can be increased along with increase in stiffness and mechanical hardness. The heterostructures were characterized in terms of structural, electrical, morphological and mechanical properties by X-ray diffraction (XRD), four probe resistivity method, atomic force microscopy, field emission scanning electron microscopy, and nanoindentation. The NiTiCu/AlN/NiTiCu heterostructure exhibit enhanced mechanical and damping properties as compared to NiTiCu/AlN and pure NiTiCu. This enhancement in hardness and damping of the heterostructure could be attributed to the shape memory effect of NiTiCu, intrinsic piezoelectricity of AlN and increased number of interfaces in heterostructure that help in dissipation of mechanical vibrations. The findings of this work provide additional impetus for the application of these heterostructures in emerging fields of nanotechnology and microelectro mechanical (MEMS) devices

Autoradiographical Detection of Tritium in Cu-Ni Alloy by Scanning Electron Microscopy

OpenAIRE

高安, 紀; 中野, 美樹; 竹内, 豊三郎

1981-01-01

The autoradiograph of tritium dispersed in Cu-Ni alloy sheet by 6Li(n,α)3H reaction was obtained by a scanning electron microscope. Prior to the irradiation of neutrons 6Li was deposited on the sheet by evaporation. The liquid emulsion, Fuji-ER, was used in this study. The distribution of tritium was detected by the dispersion of silver grains remaining in the emulsion after the development was carried out.

Phase formation in as-solidified and heat-treated Al–Si–Cu–Mg–Ni alloys: Thermodynamic assessment and experimental investigation for alloy design

International Nuclear Information System (INIS)

Farkoosh, A.R.; Javidani, M.; Hoseini, M.; Larouche, D.; Pekguleryuz, M.

2013-01-01

Highlights: ► Phase formation in Al–Si–Ni–Cu–Mg–Fe system have been investigated. ► T-Al 9 FeNi, γ-Al 7 Cu 4 Ni, δ-Al 3 CuNi and ε-Al 3 Ni are formed at different Ni levels. ► Thermally stable Ni-bearing precipitates improved the overaged hardness. ► It was found that Ni:Cu and Ni:Fe ratios control the precipitation. ► δ-Al 3 CuNi phase has more contribution to strength compare to other precipitates. - Abstract: Thermodynamic simulations based on the CALPHAD method have been carried out to assess the phase formation in Al–7Si–(0–1)Ni–0.5Cu–0.35Mg alloys (in wt.%) under equilibrium and non-equilibrium (Scheil cooling) conditions. Calculations showed that the T-Al 9 FeNi, γ-Al 7 Cu 4 Ni, δ-Al 3 CuNi and ε-Al 3 Ni phases are formed at different Ni levels. By analyzing the calculated isothermal sections of the phase diagrams it was revealed that the Ni:Cu and Ni:Fe ratios control precipitation in this alloy system. In order to verify the simulation results, microstructural investigations in as-cast, solution treated and aged conditions were carried out using electron probe microanalysis (EPMA), scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Furthermore, cooling curve analysis (CCA) was also performed to determine the freezing range of the new alloys and porosity formation during solidification. Hardness measurements of the overaged samples showed that in this alloy system the δ-Al 3 CuNi phase has a greater influence on the overall strength of the alloys compared to the other Ni-bearing precipitates.

Interfacial reactions in the Sb–Sn/(Cu, Ni) systems: Wetting experiments

International Nuclear Information System (INIS)

Novakovic, R.; Lanata, T.; Delsante, S.; Borzone, G.

2012-01-01

Interfacial reactions in the Sb–Sn/Cu and Sb–Sn/Ni systems have been investigated by means of wetting experiments. The wetting behaviour of two lead-free alloys, namely, Sb 2.5 Sn 97.5 and Sb 14.5 Sn 85.5 (at.%), in contact with Cu and Ni-substrates has been studied in view of possible applications as high-temperature solders in the electronics industry. The contact angle measurements on Cu and Ni plates were performed by using a sessile drop apparatus. The solder/substrate interface was characterised by the SEM-EDS analyses. -- Highlights: ► Sb–Sn alloys are used as high temperature lead-free solders. ► Sb–Sn alloys have good wetting properties on Cu and Ni substrates. ► Interfacial reactions and products are important for joint properties. ► Interfacial reactions/products data can be used to study the phase diagrams.

Glass forming ability and mechanical properties of the NiZrTiSi amorphous alloys modified with Al, Cu and Nb additions

International Nuclear Information System (INIS)

Czeppe, Tomasz; Ochin, Patrick; Sypien, Anna

2007-01-01

The composition of the amorphous alloy Ni 59 Zr 20 Ti 16 Si 5 was modified with 2-9 at.% additions of Cu, Al and Nb. The ribbons and the bars 2.7 mm in diameter were prepared by melt spinning and injection casting from the alloys of the compositions: Ni 56 Zr 18 Ti 16 Si 5 Al 3 Cu 2 , Ni 56 Zr 18 Ti 13 Al 6 Si 5 Cu 2 , Ni 56 Zr 16 Ti 12 Nb 9 Al 3 Cu 2 Si 2 and Ni 56 Zr 16 Ti 12 Nb 6 Al 6 Cu 2 Si 2 . All ribbons were amorphous up to the resolution of the X-ray diffraction and conventional transmission electron microscopy, however rods were partially crystalline. Increase of Al content lowered and Nb content slightly increased crystallization start temperature T x and glass transition temperature T g . The influence of composition changes on the overcooled liquid range ΔT was more complicated. The increase of Nb and decrease of Ti and Zr content led to the remarkable increase of the liquidus temperature T l . As a result GFA calculated as T g /T l was lowered to the values about 0.63 for 6 and 9 at.% Nb addition. The activation energies for primary crystallization in alloy with 6 at.% Al and 6 at.% of Nb, were determined. The changes of tensile test strength and microhardness with Al and Nb additions showed hardening effect caused by Nb additions and increase in fracture strength with increasing Al content

Hume-Rothery electron concentration rule across a whole solid solution range in a series of gamma-brasses in Cu-Zn, Cu-Cd, Cu-Al, Cu-Ga, Ni-Zn and Co-Zn alloy systems

Science.gov (United States)

Mizutani, U.; Noritake, T.; Ohsuna, T.; Takeuchi, T.

2010-05-01

The aim of the present work is to examine if the Hume-Rothery stabilisation mechanism holds across whole solid solution ranges in a series of gamma-brasses with especial attention to the role of vacancies introduced into the large unit cell. The concentration dependence of the number of atoms in the unit cell, N, for gamma-brasses in the Cu-Zn, Cu-Cd, Cu-Al, Cu-Ga, Ni-Zn and Co-Zn alloy systems was determined by measuring the density and lattice constants at room temperature. The number of itinerant electrons in the unit cell, e/uc, is evaluated by taking a product of N and the number of itinerant electrons per atom, e/a, for the transition metal element deduced earlier from the full-potential linearised augmented plane wave (FLAPW)-Fourier analysis. The results are discussed within the rigid-band model using as a host the density of states (DOS) derived earlier from the FLAPW band calculations for the stoichiometric gamma-brasses Cu5Zn8, Cu9Al4 and TM2Zn11 (TM = Co and Ni). A solid solution range of gamma-brasses in Cu-Zn, Cu-Cd, Cu-Al, Cu-Ga and Ni-Zn alloy systems is found to fall inside the existing pseudogap at the Fermi level. This is taken as confirmation of the validity of the Hume-Rothery stability mechanism for a whole solute concentration range of these gamma-brasses. An exception to this behaviour was found in the Co-Zn gamma-brasses, where orbital hybridisation effects are claimed to play a crucial role in stabilisation.

Experimental investigation of phase equilibria in the Zr-Cu-Ni ternary system

Energy Technology Data Exchange (ETDEWEB)

Yang, Mujin; Wang, Cuiping; Yang, Shuiyuan; Shi, Zhan; Han, Jiajia; Liu, Xingjun [Xiamen Univ. (China). College of Materials and Fujian Provincial Key Lab. of Materials Genome

2017-08-15

The phase equilibria in the Zr-Cu-Ni ternary system are investigated combined with X-ray diffraction, electron probe micro-analysis and differential scanning calorimetry. Two isothermal sections of the Zr-Cu-Ni ternary system at 1 000 C and 1 100 C are experimentally established. Most of the binary intermetallic compounds, e.g. Zr{sub 7}Ni{sub 10}, ZrNi, ZrNi{sub 5}, Zr{sub 14}Cu{sub 51}, and Zr{sub 2}Cu{sub 9}, show a remarkable ternary solubility. A new ternary compound named τ{sub 3} (Zr{sub 31.1-30.7} . Cu{sub 28.5-40.3}Ni{sub 40.4-29.0}) is detected at 1 000 C and dissolved at 1 020 C because the nearby large liquid phase field further expands. The newly determined phase equilibria will provide important information for both thermodynamic assessment and alloy design of Zr-based metallic glass.

Characteristics of slowly cooled Zr-Al-Cu-Ni bulk samples with different oxygen content

International Nuclear Information System (INIS)

Gebert, A.; Eckert, J.; Bauer, H.-D.; Schultz, L.

1998-01-01

Bulk samples of the glass-forming Zr 65 Al 7.5 Cu 17.5 Ni 10 and Zr 55 Al 10 Cu 30 Ni 5 alloys with 3 mm diameter were prepared by die casting into a copper mould. The oxygen content of the samples was varied between 0.26 at.% and 0.73 at.% by adjusting the oxygen partial pressure in the argon atmosphere upon casting. Characterization of the microstructure of as-cast samples and of specimens continuously heated to 873 K was carried out by X-ray diffraction (XRD), optical microscopy (OM) and transmission electron microscopy (TEM). Thermal stability was investigated by constant-rate differential scanning calorimetry (DSC). The phase formation and the thermal stability of the slowly cooled zirconium-based bulk samples are essentially influenced by the oxygen content of the material. Furthermore, the sensitivity to oxygen depends on the composition of the alloy. In bulk Zr 65 Al 7.5 Cu 17.5 Ni 10 samples only small oxygen traces induce nucleation and crystal growth during slow cooling whereas Zr 55 Al 10 Cu 30 Ni 5 samples are completely amorphous for all oxygen contents investigated. The processes of the oxygen-induced phase formation are discussed in detail also with respect to the results obtained for the heat treated samples. With increasing oxygen content the thermal stability deteriorates, as it is obvious from a diminution of the supercooled liquid region (ΔT x = T x - T g ) which is mainly due to a reduction of the crystallization temperature T x . Furthermore, the thermal behaviour of Zr 65 Al 7.5 Cu 17.5 Ni 10 and Zr 55 Al 10 Cu 30 Ni 5 reveals significant differences. (orig.)

One dimensional motion of interstitial clusters and void growth in Ni and Ni alloys

Science.gov (United States)

Yoshiie, T.; Ishizaki, T.; Xu, Q.; Satoh, Y.; Kiritani, M.

2002-12-01

One dimensional (1-D) motion of interstitial clusters is important for the microstructural evolution in metals. In this paper, the effect of 2 at.% alloying with elements Si (volume size factor to Ni: -5.81%), Cu (7.18%), Ge (14.76%) and Sn (74.08%) in Ni on 1-D motion of interstitial clusters and void growth was studied. In neutron irradiated pure Ni, Ni-Cu and Ni-Ge, well developed dislocation networks and voids in the matrix, and no defects near grain boundaries were observed at 573 K to a dose of 0.4 dpa by transmission electron microscopy. No voids were formed and only interstitial type dislocation loops were observed near grain boundaries in Ni-Si and Ni-Sn. The reaction kinetics analysis which included the point defect flow into planar sink revealed the existence of 1-D motion of interstitial clusters in Ni, Ni-Cu and Ni-Ge, and lack of such motion in Ni-Si and Ni-Sn. In Ni-Sn and Ni-Si, the alloying elements will trap interstitial clusters and thereby reduce the cluster mobility, which lead to the reduction in void growth.

Influence of Ni Solute segregation on the intrinsic growth stresses in Cu(Ni) thin films

International Nuclear Information System (INIS)

Kaub, T.M.; Felfer, P.; Cairney, J.M.; Thompson, G.B.

2016-01-01

Using intrinsic solute segregation in alloys, the compressive stress in a series of Cu(Ni) thin films has been studied. The highest compressive stress was noted in the 5 at.% Ni alloy, with increasing Ni concentration resulting in a subsequent reduction of stress. Atom probe tomography quantified Ni's Gibbsian interfacial excess in the grain boundaries and confirmed that once grain boundary saturation is achieved, the compressive stress was reduced. This letter provides experimental support in elucidating how interfacial segregation of excess adatoms contributes to the post-coalescence compressive stress generation mechanism in thin films. - Graphical abstract: Cu(Ni) film stress relationship with Ni additions. Atom probe characterization confirms solute enrichment in the boundaries, which was linked to stress response.

Synthesis and densification of Cu-coated Ni-based amorphous composite powders

International Nuclear Information System (INIS)

Kim, Yong-Jin; Kim, Byoung-Kee; Kim, Jin-Chun

2007-01-01

Spherical Ni 57 Zr 20 Ti 16 Si 2 Sn 3 (numbers indicate at.%) amorphous powders were produced by the gas atomization process, and ductile Cu phase was coated on the Ni-based amorphous powders by the spray drying process in order to increase the ductility of the consolidated amorphous alloy. The characteristics of the as-prepared powders and the consolidation behaviors of Cu-coated Ni-based amorphous composite powders were investigated. The atomization was conducted at 1450 deg. C under the vacuum of 10 -2 mbar. The Ni-based amorphous powders and Cu nitrate solution were mixed and sprayed at temperature of 130 deg. C. After spray drying and reduction treatment, the sub-micron size Cu powders were coated successfully on the surface of the atomized Ni amorphous powders. The spark plasma sintering process was applied to study the densification behavior of the Cu-coated composite powders. Thickness of the Cu layer was less than 1 μm. The compacts obtained by SPS showed high relative density of over 98% and its hardness was over 800 Hv

Effect of solute atoms on swelling in Ni alloys and pure Ni under He + ion irradiation

Science.gov (United States)

Wakai, E.; Ezawa, T.; Imamura, J.; Takenaka, T.; Tanabe, T.; Oshima, R.

2002-12-01

The effects of solute atoms on microstructural evolutions have been investigated using Ni alloys under 25 keV He + irradiation at 500 °C. The specimens used were pure Ni, Ni-Si, Ni-Co, Ni-Cu, Ni-Mn and Ni-Pd alloys with different volume size factors. The high number densities of dislocation loops about 1.5×10 22 m -3 were formed in the specimens irradiated to 1×10 19 ions/m 2, and they were approximately equivalent, except for Ni-Si. The mean size of loops tended to increase with the volume size factor of solute atoms. In a dose of 4×10 20 ions/m 2, the swelling was changed from 0.2% to 4.5%, depending on the volume size factors. The number densities of bubbles tended to increase with the absolute values of the volume size factor, and the swelling increased with the volume size factors. This suggests that the mobility of helium and vacancy atoms may be influenced by the interaction of solute atoms with them.

Spin glass and ferromagnetic properties of Ce(Cu_1_-_xNi_x)_4Mn alloys: Multicritical points in the magnetic phase diagram

International Nuclear Information System (INIS)

Synoradzki, K.; Toliński, T.

2016-01-01

We report on the CeNi_4Mn (ferromagnet FM) - CeCu_4Mn (spin-glass SG) transformation leading to a complex magnetic phase diagram (MPD). It is verified that all the Ce(Cu_1_-_xNi_x)_4Mn alloys are isostructural and the transformation is governed only by the Cu-Ni substitution. MPD is built based on the magnetic dc/ac susceptibility measurements and reveals SG formation as well as the region of the coexistence of the FM and SG state in the middle range of the Ni concentration. The complex MPD is explained by clusters formation and a competition of interactions between various crystallographic sites of the hexagonal CaCu_5-type structure, mainly the 3g-3g and 3g-2c interactions. The predominance of the SG state is confirmed by the analysis of the frequency dependence of the ac magnetic susceptibility components and the relaxation of the remanent magnetization. Additionally, the presence of two multicritical points is observed. - Highlights: • We fully characterized the magnetic properties of Ce(Cu_1_-_xNi_x)_4Mn alloys. • We show the presence of complex magnetic behaviour due to atomic-site disorder. • Magnetic phase diagram revels mixed-phase ground state. • Two multicritical points on magnetic phase diagram occurs.

Shape memory effect and microstructures of sputter-deposited Cu-Al-Ni films

International Nuclear Information System (INIS)

Minemura, T.; Andoh, H.; Kita, Y.; Ikuta, I.

1985-01-01

The shape memory effect has been found in many alloy systems which exhibit a thermoelastic martensite transformation. Cu-Al-Ni alloys exhibit an excellent shape memory effect in single crystalline states, but they have not yet been commercially used due to their brittle fracture along the grain boundaries in polycrystalline states. This letter reports the shape memory effect and microstructures of the sputter-deposited Cu-Al-Ni films. Cu-14%Al-4%Ni alloy ingot was prepared. A target for sputter deposition was cut from the ingot. Aluminium foils (20 μm thick) were used for the substrates of sputter deposition. The microstructures and crystal structures of the films were investigated by transmission electron microscopy (TEM) and X-ray diffraction using CuKα radiation, respectively. The effect of the sputtering conditions such as substrate temperature, partial pressure of argon gas, and the sputtering power on the structures of sputter-deposited Cu-14%Al-4%Ni films were investigated by X-ray diffraction. Results are shown and discussed. Photographs demonstrate shape memory behaviour of Cu-14%Al-4%Ni films sputter-deposited on aluminium foils from (a) liquid nitrogen temperature to (d) room temperature. (author)

Electrode kinetics of ethanol oxidation on novel CuNi alloy supported catalysts synthesized from PTFE suspension

Science.gov (United States)

Sen Gupta, S.; Datta, J.

An understanding of the kinetics and mechanism of the electrochemical oxidation of ethanol is of considerable interest for the optimization of the direct ethanol fuel cell. In this paper, the electro-oxidation of ethanol in sodium hydroxide solution has been studied over 70:30 CuNi alloy supported binary platinum electrocatalysts. These comprised mixed deposits of Pt with Ru or Mo. The electrodepositions were carried out under galvanostatic condition from a dilute suspension of polytetrafluoroethylene (PTFE) containing the respective metal salts. Characterization of the catalyst layers by scanning electron microscope (SEM)-energy dispersive X-ray (EDX) indicated that this preparation technique yields well-dispersed catalyst particles on the CuNi alloy substrate. Cyclic voltammetry, polarization study and electrochemical impedance spectroscopy were used to investigate the kinetics and mechanism of ethanol electro-oxidation over a range of NaOH and ethanol concentrations. The relevant parameters such as Tafel slope, charge transfer resistance and the reaction orders in respect of OH - ions and ethanol were determined.

Equilibrium phase of high-entropy FeCoNiCrCu0.5 alloy at elevated temperature

International Nuclear Information System (INIS)

Lin, C.-M.; Tsai, H.-L.

2010-01-01

The phase transformations of FeCoNiCrCu 0.5 alloy with the as-cast structure and heat-treated structures were studied. The as-cast alloy specimens were first heated at 1050 o C with a holding time of 1 h. Serial heat-treatment processes at 350 o C, 500 o C, 650 o C, 800 o C, 950 o C, 1100 o C, 1250 o C and 1350 o C with a holding time of 24 h were then carried out to understand the phase evolution and the relationship between the microstructure and the hardness of the specimens. The microstructures were investigated and chemical analyses performed by optical microscopy (OM), scanning elector microscopy (SEM), X-ray diffractometer (XRD) and transmission elector microscopy (TEM). The results show that FCC peaks were observed from the X-ray diffraction of the as-cast specimens and a precipitate phase was present in the specimens that had been heated to 950 o C. The hardness of the FeCoNiCrCu 0.5 alloy remained unchanged in the specimens that underwent various heat treatments that were applied in this study.

Two-dimensional nano-lattice in Fe-Co-Ni-Al-Cu alloys

International Nuclear Information System (INIS)

Kalanov, M.U.; Ibragimova, E.M.; Khamraeva, R.N.; Rustamova, V.M.; Ummatov, H.D.

2007-01-01

Full text: The high coercive strength of the dispersionally solidified alloys on the base of Fe-Co-Ni-Al-Cu system appears as a result of the special thermomagnetic annealing, when particles of the strong magnetic phase are distinguished in non-magnetic matrix along an external magnetic field direction. The neutron studying allows one to reveal the correlation between magnetization and inclusion axes, and also existence of magnetic microcell and perfectness of the lattice. This work presents results of neutron diffraction study with a double-crystal spectrometer (0.145 nm). Plate like samples of size 18 12 4 mm 3 were cut from a single crystal of alloy UNDK35 T5 along (100) plane. Magnetic field of 6 kOe was applied perpendicular to the neutron beam. Zero-field spectrum had only random variation of the background. Under the applied magnetic field two maxima appeared at the angles of 12 and 24 minute. In the case of the magnetic field directed in parallel to the scattering vector, the two maxima disappeared as expected. It is evidence that nuclear scattering is less than magnetic one and the observed maxima correspond to (10) and (20) reflections from a two dimensional ferro-magnetic microcell. The cell parameter of the magnetic microcell was found 40.6 nm. The coherent scattering region size was 120-160 nm. The ferro-magnetic rod diameter estimated from the peak widths was 16 nm. The diffraction pattern for the demagnetized sample strongly differs from the initial magnetized sample, where a diffuse reflection was observed near Bragg reflection and related with residual magnetization. So, the magnetic inclusions created in the Fe-Co-Ni-Al-Cu system at the thermomagnetic annealing by means of disintegration of the solid solution are strong ferro-magnetic and one-domain. These particles form the two-dimensional magnetic microcell and interact each to other within 3-4 periods of the cell. (authors)

Effect of composition on the high rate dynamic behaviour of tungsten heavy alloys

Directory of Open Access Journals (Sweden)

Latif Kesemen

2015-01-01

Full Text Available Tungsten heavy alloys are currently used as kinetic energy penetrators in military applications due to their high density and superior mechanical properties. In the literature, quasi-static properties of different tungsten heavy alloys based on W-Ni-Cu and W-Ni-Fe ternary systems are well documented and presented. However, comparison of the dynamic behaviour of these alloys in terms of the correlation between quasi-static mechanical characterization and dynamical properties is lacking. In the present study, dynamic properties of tungsten heavy alloys having different binder phase compositions (90W-7Ni-3Cu and 90W-8Ni-2Fe at different projectile velocities were investigated. The examined and tested alloys were produced through the conventional powder metallurgy route of mixing, cold compaction and sintering. Mechanical characterization of these alloys was performed. In the ballistic tests, cylindrical tungsten heavy alloys with L/D ratio of 3 were impacted to hardened steel target at different projectile velocities. After the ballistic tests, deformation characteristics of test specimens during dynamic loading were evaluated by comparing the change of length and diameter of the specimens versus kinetic energy densities. The study concluded that 90W-8Ni-2Fe alloy has better perforation characteristics than 90W-7Ni-3Cu alloy.

L10 ordered structures in Al-Cu-(Mg) alloys at the early stages of elevated temperature aging

Energy Technology Data Exchange (ETDEWEB)

Fuzhong, X.; Mingpu, W.

2016-07-01

This study concerns the precipitation structures of Al-3Cu and Al-3Cu-1.78Mg (wt. %) alloys at the early stages of elevated temperature aging. The Al-3Cu and Al-3Cu-1.78 Mg alloys were solution treated at 540 °C and 500 °C for 2 h, respectively, and then aged at 190 °C for 2 min. The precipitation structures in aged Al-3Cu-(1.78Mg) alloys were characterized by Transmission Electron Microscopy (TEM) and High Resolution Transmission Electron Microscopy (HTREM). 001 zone axis Selected area electron diffraction patterns indicate that L10 ordered structures are formed in the two aged alloys. HRTEM experiments reveal the partial dislocations on the interfaces of L10 ordered structures. From comparing experimental results with that in the literature, it is concluded that the L10 ordered structures in aged Al-3Cu alloy consist of Al and Cu atoms, and they are comprised by Al, Cu and Mg atoms together in the aged Al-3Cu-1.78Mg alloy. On the basis of precipitate growing thermodynamics, it is thought the L10 ordered structures act as nuclei for GP zones in Al-Cu-(Mg) alloys during aging. (Author)

L10 ordered structures in Al-Cu-(Mg) alloys at the early stages of elevated temperature aging

International Nuclear Information System (INIS)

Fuzhong, X.; Mingpu, W.

2016-01-01

This study concerns the precipitation structures of Al-3Cu and Al-3Cu-1.78Mg (wt. %) alloys at the early stages of elevated temperature aging. The Al-3Cu and Al-3Cu-1.78 Mg alloys were solution treated at 540 °C and 500 °C for 2 h, respectively, and then aged at 190 °C for 2 min. The precipitation structures in aged Al-3Cu-(1.78Mg) alloys were characterized by Transmission Electron Microscopy (TEM) and High Resolution Transmission Electron Microscopy (HTREM). 001 zone axis Selected area electron diffraction patterns indicate that L10 ordered structures are formed in the two aged alloys. HRTEM experiments reveal the partial dislocations on the interfaces of L10 ordered structures. From comparing experimental results with that in the literature, it is concluded that the L10 ordered structures in aged Al-3Cu alloy consist of Al and Cu atoms, and they are comprised by Al, Cu and Mg atoms together in the aged Al-3Cu-1.78Mg alloy. On the basis of precipitate growing thermodynamics, it is thought the L10 ordered structures act as nuclei for GP zones in Al-Cu-(Mg) alloys during aging. (Author)

Phase decomposition in a mechanically alloyed Cu-44.5 at%Ni-22.5 at%Fe alloy during isothermal aging

International Nuclear Information System (INIS)

Lopez-Hirata, Victor M.; Saucedo-Munoz, Maribel L.; Diaz-Barriga-Arceo, Lucia G.

2006-01-01

A supersaturated solid solution of Cu-44.5 at%Ni-22.5 at%Fe alloy was produced by ball milling of a pure chemical elemental mixture for 1080 ks. An fcc supersaturated solid solution with a grain size of about 20 nm was obtained after milling. This alloy was subsequently aged at 803, 898 and 1003 K for different times. The growth kinetics of the modulation wavelength was determined from the X-ray diffraction results and followed the Lifshitz-Slyozov-Wagner theory for a diffusion-controlled coarsening in the MA alloy after aging. The growth kinetics of composition modulation wavelength for the MA alloy was faster at 803 and 898 K than that for the same alloy composition obtained by a conventional processing and then aged at the same temperatures. The activation energy for the decomposed phase coarsening process in the MA alloy was lower than that corresponding to the conventionally-processed alloy. (author)

The specific heat of Cu-Al-Ni shape memory alloys

International Nuclear Information System (INIS)

Ruiz-Larrea, I.; Lopez-Echarri, A.; Bocanegra, E.H.; No, M.L.; San Juan, J.M.

2006-01-01

The specific heat of Cu 81.8 Al 13.7 Ni 4.5 (AK10) shape memory alloy has been studied by means of conventional DSC and adiabatic calorimetry techniques. The transformation temperatures and the shape of the calorimetric curves obtained by adiabatic calorimetry do not show any noticeable dependence on the temperature measurement rates, contrarily to what is observed by other calorimetric techniques. The dynamical character of the various experimental methods together with the influence of the latent heat associated to the first order character of these phase transitions are discussed. The specific heat of AK10 has been measured from 50 to 350 K which covers the phase transformation temperature range. The forward and reverse martensitic transformation peaks were found at 299.5 and 304.6 K, showing a thermal hysteresis of 5.1 deg. C. The C p accuracy can be estimated in 0.1% of C p and permits a reliable assignment of the following values to the phase transition thermodynamic functions: ΔH = 7.4 ± 0.2 J/g and ΔS = 0.025 ± 0.001 J/gK

Self-consistent electronic structure and segregation profiles of the Cu-Ni (001) random-alloy surface

DEFF Research Database (Denmark)

Ruban, Andrei; Abrikosov, I. A.; Kats, D. Ya.

1994-01-01

We have calculated the electronic structure and segregation profiles of the (001) surface of random Cu-Ni alloys with varying bulk concentrations by means of the coherent potential approximation and the linear muffin-tin-orbitals method. Exchange and correlation were included within the local......-density approximation. Temperature effects were accounted for by means of the cluster-variation method and, for comparison, by mean-field theory. The necessary interaction parameters were calculated by the Connolly-Williams method generalized to the case of a surface of a random alloy. We find the segregation profiles...

Effects of Nb addition on icosahedral quasicrystalline phase formation and glass-forming ability of Zr--Ni--Cu--Al metallic glasses

International Nuclear Information System (INIS)

Fan, Cang; Li, Chunfei; Inoue, Akihisa; Haas, Volker

2001-01-01

This work shows that the crystallization process of Zr--Ni--Cu--Al metallic glass is greatly influenced by adding Nb as an alloying element. Based on the results of the differential scanning calorimetry experiments for metallic glasses Zr 69-x Nb x Ni 10 Cu 12 Al 9 (x=0--15at.%), the crystallization process takes place through two individual stages. For Zr 69 Ni 10 Cu 12 Al 9 (x=0), metastable hexagonal ω-Zr and a small fraction of tetragonal Zr 2 Cu are precipitated upon completion of the first exothermic reaction. Contrary to this alloy, the precipitation of a nanoquasicrystalline phase is detected when 5--10 at.% Nb is added. Furthermore, the crystallization temperature T x , supercooled liquid region ΔT x and reduced temperature T g /T L (T g is the glass transition temperature, T L the liquidus temperature) increase with increasing Nb content. These results indicate that adding Nb content to Zr--Ni--Cu--Al metallic glasses not only induces quasicrystalline phase formation, but also enhances glass-forming ability. Copyright 2001 American Institute of Physics

First stage of the structural evolution of austenite in Cu-Al-Ni shape memory alloys

International Nuclear Information System (INIS)

Pelosin, V.; Gerland, M.; Riviere, A.

2001-01-01

Two shape memory Cu-Al-Ni alloys, a polycrystal and a single crystal, exhibiting a martensitic transformation close to 130 C (in the as-quenched state) have been studied. Specimens have been quenched after heat treatment at 850 C. The structural evolutions of the high temperature phase (austenite) have been studied for thermal treatments performed below 200 C. Investigations have been carried out using electrical resistivity measurements, TEM (transmission electron microscopy) observations and X-ray diffraction analysis. The main structural modifications are observed in the polycrystalline alloy and concern first, the reordering process of the austenite structure (B2→L2 1 ), and second, the precipitation of the (Cu 9 Al 4 ) γ 2 phase. In the single crystal alloy, the evolutions are very slight and localized on the structural defects. Particular attention is paid to the role of the quenched-in vacancy elimination on the observed mechanisms. In addition, the incidence of the structural evolution on the transformation temperatures is also discussed. (orig.)

Biocorrosion properties of antibacterial Ti-10Cu sintered alloy in several simulated biological solutions.

Science.gov (United States)

Liu, Cong; Zhang, Erlin

2015-03-01

Ti-10Cu sintered alloy has shown strong antibacterial properties against S. aureus and E. coli and good cell biocompatibility, which displays potential application in dental application. The corrosion behaviors of the alloy in five different simulated biological solutions have been investigated by electrochemical technology, surface observation, roughness measurement and immersion test. Five different simulated solutions were chosen to simulate oral condition, oral condition with F(-) ion, human body fluids with different pH values and blood system. It has been shown that Ti-10Cu alloy exhibits high corrosion rate in Saliva pH 3.5 solution and Saliva pH 6.8 + 0.2F solution but low corrosion rate in Hank's, Tyrode's and Saliva pH 6.8 solutions. The corrosion rate of Ti-10Cu alloy was in a order of Hank's, Tyrode's, Saliva pH 6.8, Saliva-pH 3.5 and Saliva pH 6.8 + 0.2F from slow to fast. All results indicated acid and F(-) containing conditions prompt the corrosion reaction of Ti-Cu alloy. It was suggested that the Cu ion release in the biological environments, especially in the acid and F(-) containing condition would lead to high antibacterial properties without any cell toxicity, displaying wide potential application of this alloy.

Atomic kinetic Monte Carlo model based on ab initio data: Simulation of microstructural evolution under irradiation of dilute Fe-CuNiMnSi alloys

International Nuclear Information System (INIS)

Vincent, E.; Becquart, C.S.; Domain, C.

2007-01-01

The embrittlement of pressure vessel steels under radiation has been long ago correlated with the presence of Cu solutes. Other solutes such as Ni, Mn and Si are now suspected to contribute also to the embrittlement. The interactions of these solutes with radiation induced point defects thus need to be characterized properly in order to understand the elementary mechanisms behind the formation of the clusters formed upon radiation. Ab initio calculations based on the density functional theory have been performed to determine the interactions of point defects with solute atoms in dilute FeX alloys (X = Cu, Mn, Ni or Si) in order to build a database used to parameterise an atomic kinetic Monte Carlo model. Some results of irradiation damage in dilute Fe-CuNiMnSi alloys obtained with this model are presented

Atomic kinetic Monte Carlo model based on ab initio data: Simulation of microstructural evolution under irradiation of dilute Fe CuNiMnSi alloys

Science.gov (United States)

Vincent, E.; Becquart, C. S.; Domain, C.

2007-02-01

The embrittlement of pressure vessel steels under radiation has been long ago correlated with the presence of Cu solutes. Other solutes such as Ni, Mn and Si are now suspected to contribute also to the embrittlement. The interactions of these solutes with radiation induced point defects thus need to be characterized properly in order to understand the elementary mechanisms behind the formation of the clusters formed upon radiation. Ab initio calculations based on the density functional theory have been performed to determine the interactions of point defects with solute atoms in dilute FeX alloys (X = Cu, Mn, Ni or Si) in order to build a database used to parameterise an atomic kinetic Monte Carlo model. Some results of irradiation damage in dilute Fe-CuNiMnSi alloys obtained with this model are presented.

Grain size and temperature influence on the toughness of a CuAlBe shape memory alloy

International Nuclear Information System (INIS)

Albuquerque, Victor Hugo C. de; Melo, Tadeu Antonio de A; Gomes, Rodinei M.; Lima, Severino Jackson G. de; Tavares, Joao Manuel R.S.

2010-01-01

Research highlights: → This work evaluated the capacity of a CuAlBe alloy to absorb energy until rupture. → The V-notch Charpy test was adopted at -150, -100, -50, 0, 50, 100 and 150 deg. C. → Charpy tests were complemented by DSC, DSC with optical microscope and by SEM. → First work to analyze the toughness of a CuAlBe alloy based on the Charpy test. → The results are of relevant value to enhance the understanding of the CuAlBe alloy. - Abstract: This work is a study of the influence of grain size and temperature on the toughness of CuAlBe shape memory alloys with (CuAlBeNbNi) and without NbNi (CuAlBe) grain refiner elements. The toughness analysis was based on the V-notch Charpy impact test under temperatures of -150, -100, -50, 0, 50, 100 and 150 deg. C. A statistical analysis of the results led to the conclusion that the toughness of both alloys was influenced by temperature and grain size. The CuAlBeNbNi alloy absorbed higher impact energy than the CuAlBe alloy showing that the refining elements improved the toughness of the alloy. To confirm and complement these findings, the fracture surfaces were evaluated by stereomicroscopy. Smooth homogeneous surfaces and rough heterogonous surfaces were detected for the CuAlBeNbNi and CuAlBe alloys, respectively. Predominately brittle zones were confirmed by scanning electron microscopy in both alloys. Furthermore, to determine the phase transformation temperatures and the associated microstructures, the alloys were assessed by conventional differential scanning calorimetry (DSC) and DSC with optical microscopy.

Grain size and temperature influence on the toughness of a CuAlBe shape memory alloy

Energy Technology Data Exchange (ETDEWEB)

Albuquerque, Victor Hugo C. de, E-mail: victor.albuquerque@fe.up.pt [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Laboratorio de Solidificacao Rapida LSR, Cidade Universitaria, S/N 58059-900 Joao Pessoa, PB (Brazil); Melo, Tadeu Antonio de A, E-mail: tadeu@lsr.ct.ufpb.br [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Laboratorio de Solidificacao Rapida LSR, Cidade Universitaria, S/N 58059-900 Joao Pessoa, PB (Brazil); Gomes, Rodinei M., E-mail: gomes@lsr.ct.ufpb.br [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Laboratorio de Solidificacao Rapida LSR, Cidade Universitaria, S/N 58059-900 Joao Pessoa, PB (Brazil); Lima, Severino Jackson G. de, E-mail: jackson@lsr.ct.ufpb.br [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Laboratorio de Solidificacao Rapida LSR, Cidade Universitaria, S/N 58059-900 Joao Pessoa, PB (Brazil); Tavares, Joao Manuel R.S., E-mail: tavares@fe.up.pt [Faculdade de Engenharia da Universidade do Porto (FEUP), Departamento de Engenharia Mecanica (DEMec)/Instituto de Engenharia Mecanica e Gestao Industrial INEGI, Rua Dr. Roberto Frias, S/N 4200-465 Porto (Portugal)

2010-11-25

Research highlights: {yields} This work evaluated the capacity of a CuAlBe alloy to absorb energy until rupture. {yields} The V-notch Charpy test was adopted at -150, -100, -50, 0, 50, 100 and 150 deg. C. {yields} Charpy tests were complemented by DSC, DSC with optical microscope and by SEM. {yields} First work to analyze the toughness of a CuAlBe alloy based on the Charpy test. {yields} The results are of relevant value to enhance the understanding of the CuAlBe alloy. - Abstract: This work is a study of the influence of grain size and temperature on the toughness of CuAlBe shape memory alloys with (CuAlBeNbNi) and without NbNi (CuAlBe) grain refiner elements. The toughness analysis was based on the V-notch Charpy impact test under temperatures of -150, -100, -50, 0, 50, 100 and 150 deg. C. A statistical analysis of the results led to the conclusion that the toughness of both alloys was influenced by temperature and grain size. The CuAlBeNbNi alloy absorbed higher impact energy than the CuAlBe alloy showing that the refining elements improved the toughness of the alloy. To confirm and complement these findings, the fracture surfaces were evaluated by stereomicroscopy. Smooth homogeneous surfaces and rough heterogonous surfaces were detected for the CuAlBeNbNi and CuAlBe alloys, respectively. Predominately brittle zones were confirmed by scanning electron microscopy in both alloys. Furthermore, to determine the phase transformation temperatures and the associated microstructures, the alloys were assessed by conventional differential scanning calorimetry (DSC) and DSC with optical microscopy.

Comparative analysis of Nb and Ti addition in the Cu-11,8%wt.Al-0,5%wt.Be e Cu-11,8%wt.Al-3,0%wt.Ni shape memory alloy

International Nuclear Information System (INIS)

Silva Junior, M.Q. da; Oliveira, G.D. de

2014-01-01

The system of the Cu-Al alloys shape memory alloy have been the subject of many studies due to a wide range of possible applications and relatively low cost, and the chemical composition of the main factors that determine the properties of these properties. This work analyzed the influence of Nb and Ti elements in Cu-11,8Al-0,5Be and Cu-11,8Al-3,0Ni alloy. The alloys are obtained by melting and passed through homogenizing heat treatment followed by water quenching at 30°C. The samples were characterized by Microscopy Optical, X-ray Diffraction and Microhardness testing. The alloys showed fine precipitates of second phase homogeneously distributed in the matrix that provides improvement in the properties of these alloys. (author)

Microscopy modifications in an aged Cu-Al-Ni-Mn alloy; Modificacoes microestruturais em uma liga Cu-Al-Ni-Mn submetida ao envelhecimento

Energy Technology Data Exchange (ETDEWEB)

Gama, J.L.L. [Instituto Federal de Alagoas (IFAL), Maceio, AL (Brazil); Ferreira, R.A.S., E-mail: jorgelauriano@gmail.co [Universidade Federal de Pernambuco (DEM/UFPE), Recife, PE (Brazil). Dept. de Engenharia Mecanica

2010-07-01

An Cu-12Al-4Ni-3Mn shape memory alloy have been manufactured using an induction furnace of 24 KVA. After melting, chemical analyse was performed by X-ray fluorescence (XRF). The phase transformation of this alloy was studied in the different sequences produced during thermomechanic treatments. After homogenization, the ingot was solution treated at 850 deg C. At 750 deg C samples were submitted to a reduction by rolling to about 30% in thickness, followed by water quenching. In sequence, the ingot was cold-rolled at different thicknesses. In deformed state, sample of this alloy was submitted to the thermal analyse-DTA for identification of the phase transformation domains. For each identified domain, ageing was carried out, at different times, to evaluate the presence of the different phases. Samples were characterized ray-X diffraction. The results showed that the microstructural evolutions are of a complex nature. At 425 deg C temperature both recrystallization and precipitation of different phases were simultaneously observed. (author)

Elevated-Temperature Corrosion of CoCrCuFeNiAl0.5Bx High-Entropy Alloys in Simulated Syngas Containing H2S

Energy Technology Data Exchange (ETDEWEB)

Dogan, Omer N; Nielsen, Benjamin C; Hawk, Jeffrey A

2013-08-01

High-entropy alloys are formed by synthesizing five or more principal elements in equimolar or near equimolar concentrations. Microstructure of the CoCrCuFeNiAl{sub 0.5}B{sub x} (x = 0, 0.2, 0.6, 1) high-entropy alloys under investigation is composed of a mixture of disordered bcc and fcc phases and borides. These alloys were tested gravimetrically for their corrosion resistance in simulated syngas containing 0, 0.01, 0.1, and 1 % H{sub 2}S at 500 °C. The exposed coupons were characterized using XRD and SEM. No significant corrosion was detected at 500 °C in syngas containing 0 and 0.01 % H{sub 2}S while significant corrosion was observed in syngas containing 0.1 and 1 % H{sub 2}S. Cu{sub 1.96}S was the primary sulfide in the external corrosion scale on the low-boron high-entropy alloys, whereas FeCo{sub 4}Ni{sub 4}S{sub 8} on the high-boron high-entropy alloys. Multi-phase Cu-rich regions in the low-B high-entropy alloys were vulnerable to corrosive attack.

Dislocation structure evolution and characterization in the compression deformed Mn-Cu alloy

International Nuclear Information System (INIS)

Zhong, Y.; Yin, F.; Sakaguchi, T.; Nagai, K.; Yang, K.

2007-01-01

Dislocation densities and dislocation structure arrangements in cold compressed polycrystalline commercial M2052 (Mn-20Cu-5Ni-2Fe) high damping alloy with various strains were determined in scanning mode by X-ray peak profile analysis and electron backscatter diffraction (EBSD). The results indicate that the Mn-Cu-Ni-Fe alloy has an evolution behavior quite similar to the dislocation structure in copper. The dislocation arrangement parameter shows a local minimum in the transition range between stages III and IV that can be related to the transformation of the dislocation arrangement in the cell walls from a polarized dipole wall (PDW) into a polarized tile wall (PTW) structure. This evolution is further confirmed by the results of local misorientation determined by EBSD. In addition, during deformation, the multiplication of dislocation densities in the MnCu alloy is significantly slower than that in copper, and the transition of the dislocation structure is strongly retarded in the MnCu alloy compared with copper. These results can be explained by the mechanism of elastic anisotropy on the dislocation dynamics, as the elastic anisotropy in the MnCu alloy is larger than that in copper, which can strongly retard the multiplication of the dislocation population and the transformation of the dislocation structure. These results are important for research into the plastic working behavior of Mn-Cu-Ni-Fe high damping alloy

Effect of solute atom concentration on vacancy cluster formation in neutron-irradiated Ni alloys

Science.gov (United States)

Sato, Koichi; Itoh, Daiki; Yoshiie, Toshimasa; Xu, Qiu; Taniguchi, Akihiro; Toyama, Takeshi

2011-10-01

The dependence of microstructural evolution on solute atom concentration in Ni alloys was investigated by positron annihilation lifetime measurements. The positron annihilation lifetimes in pure Ni, Ni-0.05 at.%Si, Ni-0.05 at.%Sn, Ni-Cu, and Ni-Ge alloys were about 400 ps even at a low irradiation dose of 3 × 10 -4 dpa, indicating the presence of microvoids in these alloys. The size of vacancy clusters in Ni-Si and Ni-Sn alloys decreased with an increase in the solute atom concentration at irradiation doses less than 0.1 dpa; vacancy clusters started to grow at an irradiation dose of about 0.1 dpa. In Ni-2 at.%Si, irradiation-induced segregation was detected by positron annihilation coincidence Doppler broadening measurements. This segregation suppressed one-dimensional (1-D) motion of the interstitial clusters and promoted mutual annihilation of point defects. The frequency and mean free path of the 1-D motion depended on the solute atom concentration and the amount of segregation.

Concentration dependence of solute atoms on vacancy cluster formation in neutron irradiated Ni alloy

International Nuclear Information System (INIS)

Sato, K.; Itoh, D.; Yoshiie, T.; Xu, Q.

2007-01-01

Full text of publication follows: One dimensional (1-D) motion of interstitial clusters is important for the microstructural evolution in metals. The movement of interstitial clusters was often observed in neutron irradiated metals by transmission electron microscopy (TEM). Alloying elements are expected to affect the motion of interstitial clusters. Yoshiie et al. have studied the effect of alloying elements in Ni. For example, in neutron irradiated pure Ni, well-developed dislocation networks and voids were observed at 573 K at a dose of 0.026 dpa by TEM. After the addition of 2at.%Si (-5.81% volume size factor to Ni) and Sn (74.08% volume size factor), no voids were detected by TEM observation and positron lifetime measurement. Alloying elements of Si and Sn were expected to prevent the 1-D motion of the interstitial clusters. In this study, the concentration dependence of alloying elements on the 1-D motion of the interstitial clusters was investigated by positron annihilation lifetime measurements, and the microstructural evolution was discussed. Specimens irradiated were 99.99 pure Ni (Johnson Matthey) and Ni based binary alloys, which contain Si, Cu, Ge and Sn as solute atoms. The concentration of solute atoms was 0.05at.%o, 0.3at.% and 2at.%. Neutron irradiation was performed with the Kyoto University Reactor (KUR) and Japan materials testing reactor (JMTR) at Japan Atomic Energy Agency. Neutron dose was 6x10 -5 -1x10 -2 dpa at KUR, and 8x10 -3 -0.3 dpa at JMTR. Irradiation temperature was 573 K at KUR and 563 K at JMTR. After the neutron irradiation, positron annihilation lifetime measurements were performed at room temperature. Microvoids were detected in pure Ni, Ni-0.05%Si, Ni-0.05%Sn, Ni-Cu and Ni-Ge alloys. In Ni-Si and Ni-Sn alloys, the size of microvoids decreased as the concentration of solute atoms increased. This is because the frequency of 1-D motion of the interstitial clusters depends on the alloy concentration. High concentration of alloying

Concentration dependence of solute atoms on vacancy cluster formation in neutron irradiated Ni alloy

Energy Technology Data Exchange (ETDEWEB)

Sato, K.; Itoh, D.; Yoshiie, T.; Xu, Q. [Kyoto Univ., Research Reactor Institute, Osaka (Japan)

2007-07-01

Full text of publication follows: One dimensional (1-D) motion of interstitial clusters is important for the microstructural evolution in metals. The movement of interstitial clusters was often observed in neutron irradiated metals by transmission electron microscopy (TEM). Alloying elements are expected to affect the motion of interstitial clusters. Yoshiie et al. have studied the effect of alloying elements in Ni. For example, in neutron irradiated pure Ni, well-developed dislocation networks and voids were observed at 573 K at a dose of 0.026 dpa by TEM. After the addition of 2at.%Si (-5.81% volume size factor to Ni) and Sn (74.08% volume size factor), no voids were detected by TEM observation and positron lifetime measurement. Alloying elements of Si and Sn were expected to prevent the 1-D motion of the interstitial clusters. In this study, the concentration dependence of alloying elements on the 1-D motion of the interstitial clusters was investigated by positron annihilation lifetime measurements, and the microstructural evolution was discussed. Specimens irradiated were 99.99 pure Ni (Johnson Matthey) and Ni based binary alloys, which contain Si, Cu, Ge and Sn as solute atoms. The concentration of solute atoms was 0.05at.%o, 0.3at.% and 2at.%. Neutron irradiation was performed with the Kyoto University Reactor (KUR) and Japan materials testing reactor (JMTR) at Japan Atomic Energy Agency. Neutron dose was 6x10{sup -5}-1x10{sup -2} dpa at KUR, and 8x10{sup -3} -0.3 dpa at JMTR. Irradiation temperature was 573 K at KUR and 563 K at JMTR. After the neutron irradiation, positron annihilation lifetime measurements were performed at room temperature. Microvoids were detected in pure Ni, Ni-0.05%Si, Ni-0.05%Sn, Ni-Cu and Ni-Ge alloys. In Ni-Si and Ni-Sn alloys, the size of microvoids decreased as the concentration of solute atoms increased. This is because the frequency of 1-D motion of the interstitial clusters depends on the alloy concentration. High

Resistance to sulfur poisoning of Ni-based alloy with coinage (IB) metals

International Nuclear Information System (INIS)

Xu, Xiaopei; Zhang, Yanxing; Yang, Zongxian

2015-01-01

Highlights: • The effects of IB metal dopants on the S poisoning features of Ni are analyzed. • IB metal dopants can modify the surface electronic structure of Ni. • IB metal dopants can increase the S tolerance of Ni at an optimized concentration. • Au is a preferred dopant to increase the resistance to sulfur poisoning of Ni. - Abstract: The poisoning effects of S atom on the (1 0 0), (1 1 0) and (1 1 1) metal surfaces of pure Ni and Ni-based alloy with IB (coinage) metals (Cu, Ag, Au) are systematically studied. The effects of IB metal dopants on the S poisoning features are analyzed combining the density functional theory (DFT) results with thermodynamics data using the ab initio atomistic thermodynamic method. It is found that introducing IB doping metals into Ni surface can shift the d-band center downward from the Fermi level and weaken the adsorption of S on the (1 0 0) and (1 1 0) surfaces, and the S tolerance ability increases in the order of Ni, Cu/Ni, Ag/Ni and Au/Ni. Nevertheless, on the (1 1 1) surface, the S tolerance ability increases in the order of Ag/Ni (or Cu/Ni), Ni, and Au/Ni. When we increase the coverage of the IB metal dopants, we found that not only Au, but Cu and Ag can increase its S tolerance. We therefore propose that alloying can increase its S tolerance and alloying with Au would be a better way to increase the resistance to sulfur poisoning of the Ni anode as compared with the pure Ni and the Ag- or, Cu-doped Ni materials.

Microstructure, transformation behavior and mechanical properties of a (Ti{sub 50}Ni{sub 38}Cu{sub 12}){sub 93}Nb{sub 7} alloy

Energy Technology Data Exchange (ETDEWEB)

Jiang, Daqiang, E-mail: daqiang.jiang@uwa.edu.au [School of Mechanical and Chemical Engineering, The University of Western Australia (Australia); Department of Materials Science and Engineering, China University of Petroleum, Beijing (China); Liu, Yinong [School of Mechanical and Chemical Engineering, The University of Western Australia (Australia); Liu, Weilong; Song, Lixie; Jiang, Xiaohua [Department of Materials Science and Engineering, China University of Petroleum, Beijing (China); Yang, Hong [School of Mechanical and Chemical Engineering, The University of Western Australia (Australia); Cui, Lishan [Department of Materials Science and Engineering, China University of Petroleum, Beijing (China)

2015-03-11

A (Ti{sub 50}Ni{sub 38}Cu{sub 12}){sub 93}Nb{sub 7} alloy is fabricated by arc melting, forging and drawing. The microstructure, transformation behavior and mechanical properties were investigated by means of scanning electron microscope (SEM), differential scanning calorimeter (DSC), dynamic mechanical analyzer (DMA) and tensile test machine. SEM observation showed that the as cast alloy is composed of TiNiCu and Nb-rich phases. After drawing, the alloy showed single step transformations during heating and cooling within the whole annealing temperature range from 400 °C to 800 °C. With the increase of the annealing temperature, both the transformation temperatures and the damping capacity increased first and then decreased. The ultimate strength of the alloy after annealing at 400 °C is over 1500 MPa and the maximum elongation of the alloy after annealing at 800 °C is more than 20%.

Formation of Al70Cu20Fe10 icosahedral quasicrystal by mechanically alloyed method

International Nuclear Information System (INIS)

Yin Shilong; Bian Qing; Qian Liying; Zhang Aimei

2007-01-01

The structural evolutions of the mechanically alloyed ternary Al 70 Cu 20 Fe 10 powders with the milling time and the annealing treatment have been studied by X-ray diffraction (XRD), transmission electronic microscopy (TEM) and X-ray absorption fine-structure spectroscopy (XAFS) techniques. Results show that an Al 2 Cu compound forms with short-time milling, while a Cu 9 Al 4 compound forms with long-time milling. Fe can react with Al-Cu alloy by annealing treatment. Al 7 Cu 2 Fe compound with tetragonal structure or Al (Cu, Fe) solid solution with cubic structure may form at lower temperature, while a quasicrystal phase of Al 65 Cu 20 Fe 15 alloy may form at higher temperature

Damping characteristics of a Ti40.5Ni49.5Zr10 shape memory alloy

International Nuclear Information System (INIS)

Hsieh, S.F.; Wu, S.K.

2005-01-01

Ti 40.5 Ni 49.5 Zr 10 alloy undergoes B2-bar B19' martensitic transformation. Damping capacities of B19' and B2 phases of this alloy are lower than those of Ti 51 Ni 49 alloy due to Zr atoms solid-soluted hardening. Transformation temperatures of this alloy decrease, but transformation peak heights Q max -1 increase with increasing aging time at 300 o C due to the formation of finer (001) M twins for specimens aged longer. The Q max -1 peaks of the slightly cold-rolled Ti 40.5 Ni 49.5 Zr 10 alloy are higher than those of the as-annealed alloy, which may be because the thinner twins are induced by small deformation

Alloying effect on hardening of martensite stainless steels of the Fe-Cr-Ni and Fe-Cr-Co systems

International Nuclear Information System (INIS)

Fel'dgandler, Eh.G.; Savkina, L.Ya.

1975-01-01

The effect of alloying elements is considered on the γ → a-transformation and hardening of certain compositions of the ternary Fe-Cr-Ni- and Fe-Cr-Co alloy systems with the martensite structure. In martensite Fe-(10 to 14)% Cr base steels the elements Co, Cu, W, Ni, Mo, Si, Cr decrease, Mn, Si, Mo, Cu increase, and Cr, Ni, Co decrease the temperature of α → γ-transition. The tempering of martensite steels of the Fe-Cr-Ni- and Fe-Cr-Co-systems containing 10 to 14% Cr, 4 to 9% Ni, and 7 to 12% Co does not lead to hardening. Alloyage of the martensite Fe-Cr-Ni-, Fe-Cr-Co- and Fe-Cr-Ni-Co base separately with Mo, W, Si or Cu leads to a hardening during tempering, the hardening being the higher, the higher is the content of Ni and, especially, of Co. The increase in the content of Mo or Si produces the same effect as the increase in the Co content. In on Fe-Cr-Co or Fe-Cr-Ni-Co based steels alloyed with Mo or Si, two temperature ranges of ageing have been revealed which, evidently, have different hardening natures. The compositions studied could serve as the base material for producing maraging stainless steels having a complex variety of properties

The effect of applied stress on the shape memory behavior of TiNi-based alloys with different consequences of martensitic transformations

International Nuclear Information System (INIS)

Meisner, L.L.; Sivokha, V.P.

2004-01-01

The development of plastic deformation and shape memory behavior of the Ti 49.5 Ni 50.5 , Ti 50 Ni 34 Pt 16 , Ti 50 Ni 39,25 Cu 10 Fe 0,75 alloys are studied. The alloys differ by consequences of martensitic transformations (MT). It is found that the behavior of both accumulated and returned strain components exhibit some features in the alloys under consideration. The strain-temperature diagrams of the Ti 49.5 Ni 50.5 alloy with the B2↔B19' MT are of the one-step form. There are three stages on the strain-stress curves of this alloy depending on value of the applied mechanical torque. The regularity of plastic behavior of the Ti 50 Ni 34 Pt 16 alloy with the B2↔B19 transformation is similar to that of the Ti 49.5 Ni 50.5 alloy. The strain-stress diagram has three stages. However, there is a significant difference in the shape memory behavior of this alloy. The shape-memory behavior of the Ti 50 Ni 39,25 Cu 10 Fe 0,75 alloy corresponds to the two-stage nature of its B2↔B19↔B19' MT. The deformation mechanisms for these stages have their features in contrast to those of the foregoing alloys. The strain and temperature parameters of the shape memory effect and plastic behavior of the TiNi-based alloys are also examined

Exchange correlation length and magnetoresistance in Fe-Cu and Fe-Cu-Ni melt-spun ribbons

International Nuclear Information System (INIS)

El Ghannami, M.; Gomez-Polo, C.; Rivero, G.; Hernando, A.

1994-01-01

The magnetic properties of Fe 30 Cu 70 melt-spun ribbons are reported for the first time. In the as-cast state, the microstructure consists of b.c.c.-Fe grains immersed in a Cu-rich matrix. However, the addition of a small percentage of Ni gives rise to the appearance of new Cu-Fe-Ni phases. Under suitable thermal treatments, the microstructure of both alloys evolves towards a complete phase segregation in b.c.c-Fe and f.c.c.-Cu immiscibles phases. The temperature dependence of the magnetic properties is analysed and related to the microstructural changes produced during the thermal treatments. Remarkable magneto-resistance effects have been observed in both as-cast alloys, with maximum values of the order of 6% at low measuring temperatures. (orig.)

Transient Liquid Phase Bonding of Cu-Cr-Zr-Ti Alloy Using Ni and Mn Coatings: Microstructural Evolution and Mechanical Properties

Science.gov (United States)

Venkateswaran, T.; Ravi, K. R.; Sivakumar, D.; Pant, Bhanu; Janaki Ram, G. D.

2017-08-01

High-strength copper alloys are used extensively in the regenerative cooling parts of aerospace structures. Transient liquid phase (TLP) bonding of a Cu-Cr-Zr-Ti alloy was attempted in the present study using thin layers of elemental Ni and Mn coatings applied by electroplating. One of the base metals was given a Ni coating of 4 µm followed by a Mn coating of 15 µm, while the other base metal was given only the Ni coating (4 µm). The bonding cycle consisted of the following: TLP stage—heating to 1030 °C and holding for 15 min; homogenization stage—furnace cooling to 880 °C and holding for 2 h followed by argon quenching to room temperature. Detailed microscopy and electron probe microanalysis analysis of the brazed joints were carried out. The braze metal was found to undergo isothermal solidification within the 15 min of holding time at 1030 °C. At the end of TLP stage, the braze metal showed a composition of Cu-17Ni-9Mn (wt.%) at the center of the joint with a steep gradient in Ni and Mn concentrations from the center of the braze metal to the base metal interfaces. After holding for 2 h at 880 °C (homogenization stage), the compositional gradients were found to flatten significantly and the braze metal was found to develop a homogeneous composition of Cu-11Ni-7Mn (wt.%) at the center of the joint. In lap-shear tests, failures were always found to occur in the base metal away from the brazed region. The copper alloy base metal was found to undergo significant grain coarsening due to high-temperature exposure during brazing and, consequently, suffer considerable reduction in yield strength.

Texture development and anisotropic behaviour of a TI-44.2NI4.9CU (AT.%) shape memory alloy

NARCIS (Netherlands)

Zhao, L.

1997-01-01

The objective of this work was to determine the relationship between texture development and anisotropy of shape memory properties. A commercial Ti-45Ni-5Cu (at.%) shape memory alloy was selected. Textures were developed by controlling rolling parameters, such as rolling temperature, intermediate

Neutron irradiation effect on thermomechanical properties of shape memory alloys

International Nuclear Information System (INIS)

Abramov, V.Ya.; Ionajtis, R.R.; Kotov, V.V.; Loguntsev, E.N.; Ushakov, V.P.

1996-01-01

Alloys of Ti-Ni, Ti-Ni-Pd, Fe-Mn-Si, Mn-Cu-Cr, Mn-Cu, Cu-Al-Mn, Cu-Al-Ni systems are investigated after irradiation in IVV-2M reactor at various temperatures with neutron fluence of 10 19 - 10 20 cm -2 . The degradation of shape memory effect in titanium nickelide base alloys is revealed after irradiation. Mn-Cu and Mn-Cu-Cr alloys show the best results. Trends in shape memory alloy behaviour depending on irradiation temperature are found. A consideration is given to the possibility of using these alloys for components of power reactor control and protection systems [ru

H-Phase Precipitation and Martensitic Transformation in Ni-rich Ni-Ti-Hf and Ni-Ti-Zr High-Temperature Shape Memory Alloys

Science.gov (United States)

Evirgen, A.; Pons, J.; Karaman, I.; Santamarta, R.; Noebe, R. D.

2018-03-01

The distributions of H-phase precipitates in Ni50.3Ti29.7Hf20 and Ni50.3Ti29.7Zr20 alloys formed by aging treatments at 500 and 550 °C or slow furnace cooling and their effects on the thermal martensitic transformation have been investigated by TEM and calorimetry. The comparative study clearly reveals faster precipitate-coarsening kinetics in the NiTiZr alloy than in NiTiHf. For precipitates of a similar size of 10-20 nm in both alloys, the martensite plates in Ni50.3Ti29.7Zr20 have larger widths and span a higher number of precipitates compared with the Ni50.3Ti29.7Hf20 alloy. However, for large H-phase particles with hundreds of nm in length, no significant differences in the martensitic microstructures of both alloy systems have been observed. The martensitic transformation temperatures of Ni50.3Ti29.7Hf20 are 80-90 °C higher than those of Ni50.3Ti29.7Zr20 in the precipitate-free state and in the presence of large particles of hundreds on nm in length, but this difference is reduced to only 10-20 °C in samples with small H-phase precipitates. The changes in the transformation temperatures are consistent with the differences in the precipitate distributions between the two alloy systems observed by TEM.

Martensitic transition near room temperature and the temperature- and magnetic-field-induced multifunctional properties of Ni49CuMn34In16 alloy

Science.gov (United States)

Sharma, V. K.; Chattopadhyay, M. K.; Khandelwal, A.; Roy, S. B.

2010-11-01

A near room-temperature martensitic transition is observed in the ferromagnetic austenite state of Ni50Mn34In16 alloy with 2% Cu substitution at the Ni site. Application of magnetic field in the martensite state induces a reverse martensitic transition in this alloy. dc magnetization, magnetoresistance and strain measurements in this alloy reveal that associated with this martensitic transition there exist a large magnetocaloric effect, a large magnetoresitance and a magnetic-field temperature-induced strain. This NiMnIn alloy system thus is an example of an emerging class of magnetic materials whose physical properties can be tuned by suitable chemical substitutions, to achieve magnetic-field and temperature-induced multifunctional properties at and around room temperature

Formation of Ti--Zr--Cu--Ni bulk metallic glasses

International Nuclear Information System (INIS)

Lin, X.H.; Johnson, W.L.

1995-01-01

Formation of bulk metallic glass in quaternary Ti--Zr--Cu--Ni alloys by relatively slow cooling from the melt is reported. Thick strips of metallic glass were obtained by the method of metal mold casting. The glass forming ability of the quaternary alloys exceeds that of binary or ternary alloys containing the same elements due to the complexity of the system. The best glass forming alloys such as Ti 34 Zr 11 Cu 47 Ni 8 can be cast to at least 4-mm-thick amorphous strips. The critical cooling rate for glass formation is of the order of 250 K/s or less, at least two orders of magnitude lower than that of the best ternary alloys. The glass transition, crystallization, and melting behavior of the alloys were studied by differential scanning calorimetry. The amorphous alloys exhibit a significant undercooled liquid region between the glass transition and first crystallization event. The glass forming ability of these alloys, as determined by the critical cooling rate, exceeds what is expected based on the reduced glass transition temperature. It is also found that the glass forming ability for alloys of similar reduced glass transition temperature can differ by two orders of magnitude as defined by critical cooling rates. The origins of the difference in glass forming ability of the alloys are discussed. It is found that when large composition redistribution accompanies crystallization, glass formation is enhanced. The excellent glass forming ability of alloys such as Ti 34 Zr 11 Cu 47 Ni 8 is a result of simultaneously minimizing the nucleation rate of the competing crystalline phases. The ternary/quaternary Laves phase (MgZn 2 type) shows the greatest ease of nucleation and plays a key role in determining the optimum compositions for glass formation. copyright 1995 American Institute of Physics

Formation of two-way shape memory effect in rapid-quenched TiNiCu alloys

International Nuclear Information System (INIS)

Shelyakov, A.V.; Bykovsky, Yu.A.; Matveeva, N.M.; Kovneristy, Yu.K.

1995-01-01

Recently we have developed a number of devices for an optical radiation control based on the shape memory effect. A blind of rapid-quenched TiNiCu alloy having a two-way shape memory in bending was used as a basic element. So far as the rapid quenched alloy used is amorphous in initial state, it needs thermal annealing to form shape memory. This paper describes procedure of thermo-mechanical treatment, that allows to form desired two-way shape memory immediately during thermal annealing of amorphous alloy without training. It was shown that degree of two-way shape recovery depends critically on initial strain, temperature and duration of the annealing. It was experimentally determined optimum parameters of thermo-mechanical treatment to achieve maximum two-way shape memory. (orig.)

Ternary systems Sr-{Ni,Cu}-Si: Phase equilibria and crystal structure of ternary phases

International Nuclear Information System (INIS)

Nasir, Navida; Melnychenko-Koblyuk, Nataliya; Grytsiv, Andriy; Rogl, Peter; Giester, Gerald; Wosik, Jaroslaw; Nauer, Gerhard E.

2010-01-01

Phase relations were established in the Sr-poor part of the ternary systems Sr-Ni-Si (900 deg. C) and Sr-Cu-Si (800 deg. C) by light optical microscopy, electron probe microanalysis and X-ray diffraction on as cast and annealed alloys. Two new ternary compounds SrNiSi 3 (BaNiSn 3 -type) and SrNi 9-x Si 4+x (own-type) were found in the Sr-Ni-Si system along with previously reported Sr(Ni x Si 1-x ) 2 (AlB 2 -type). The crystal structure of SrNi 9-x Si 4+x (own-type, x=2.7, a=0.78998(3), c=1.1337(2) nm; space group P4/nbm) was determined from X-ray single crystal counter to be a low symmetry derivative of the cubic, parent NaZn 13 -type. At higher Si-content X-ray Rietveld refinements reveal the formation of a vacant site (□) corresponding to a formula SrNi 5.5 Si 6.5 □ 1.0 . Phase equilibria in the Sr-Cu-Si system are characterized by the compounds SrCu 2-x Si 2+x (ThCr 2 Si 2 -type), Sr(Cu x Si 1-x ) 2 (AlB 2 -type), SrCu 9-x Si 4+x (0≤x≤1.0; CeNi 8.5 Si 4.5 -type) and SrCu 13-x Si x (4≤x≤1.8; NaZn 13 -type). The latter two structure types appear within a continuous solid solution. Neither a type-I nor a type-IX clathrate compound was encountered in the Sr-{Cu,Ni}-Si systems. Structural details are furthermore given for about 14 new ternary compounds from related alloy systems with Ba. - Graphical abstract: The crystal structure of SrNi 9-x Si 4+x (own-type, x=2.7, a=0.78998(3), c=1.1337(2) nm; space group P4/nbm) was determined from X-ray single crystal counter to be a low symmetry derivative of the cubic, parent NaZn 13 -type and is related to CeNi 8.5 Si 4.5 -type.

Abnormal magnetization behaviors in Sm–Ni–Fe–Cu alloys

International Nuclear Information System (INIS)

Yang, W.Y.; Zhang, Y.F.; Zhao, H.; Chen, G.F.; Zhang, Y.; Du, H.L.; Liu, S.Q.; Wang, C.S.; Han, J.Z.; Yang, Y.C.; Yang, J.B.

2016-01-01

The magnetization behaviors in Sm–Ni–Fe–Cu alloys at low temperatures have been investigated. It was found that the hysteresis loops show wasp-waisted character at low temperatures, which has been proved to be related to the existence of multi-phases, the Fe/Ni soft magnetic phases and the CaCu 5 -type hard magnetic phase. A smooth-jump behavior of the magnetization is observed at T>5 K, whereas a step-like magnetization process appears at T<5 K. The CaCu 5 -type phase is responsible for such abnormal magnetization behavior. The magnetic moment reversal model with thermal activation is used to explain the relation of the critical magnetic field (H cm ) to the temperature (T>5 K). The reversal of the moment direction has to cross over an energy barrier of about 6.6×10 −15 erg. The step-like jumps of the magnetization below 5 K is proposed to be resulted from a sharp increase of the sample temperature under the heat released by the irreversible domain wall motion. - Highlights: • Two different magnetization mechanisms, controlled by temperature, have been found in the Sm–Ni–Fe–Cu alloys. The smooth-jump behavior of the magnetization is observed at T>5 K and the step-like magnetization process appears at T<5 K. • The magnetic moment reversal model with thermal activation has been successfully used to explain the relation of the critical magnetic field (H cm ) to the temperature (T>5 K). The energy barrier for the reversal of the moment direction has been found to be about 6.6×10 −15 erg. • The transition field for the step-like jumps is very strict, independent from the magnetic sweep rate. This is remarkably different from the similar step-like jump behavior in reference [20]. • According to the SEM images and EDX analysis, two kinds of regions are found in the alloys. The Fe–Ni–Cu regions are surrounded by the 1:5 Sm–Ni–Fe–Cu regions and shows fish-bone like structure. An interesting thing is that the Fe–Ni–Cu regions are

Investigation of Mechanical Properties and Plastic Deformation Behavior of (Ti45Cu40Zr10Ni5100−xAlx Metallic Glasses by Nanoindentation

Directory of Open Access Journals (Sweden)

Lanping Huang

2014-01-01

Full Text Available The effect of Al addition on mechanical properties and plastic deformation behavior of (Ti45Cu40Zr10Ni5100−xAlx (x = 0, 2, 4, 6 and 8 amorphous alloy ribbons have been investigated by nanoindentation. The hardness and elastic modulus do not simply increase with the increase of Al content. The alloy with 8 at.% Al exhibits the highest hardness and elastic modulus. The serrations or pop-in events are strongly dependent on the loading rate and alloy composition.

Study of the ternary alloy systems Al-Ni-Fe and Al-Cu-Ru with special regard to quasicrystalline phases

International Nuclear Information System (INIS)

Lemmerz, U.

1996-07-01

Two ternary alloy-systems, the Al-Ni-Fe system and the Al-Cu-Ru system were studied with special regard to quasicrystalline phases. Isothermal sections were established in both systems in the stoichiometric area of the quasicrystalline phase. In the Al-Ni-Fe system a new stable decagonal phase was found. Its stoichiometric range is very small around Al 71.6 Ni 23.0 Fe 5.4 . The temperature range in which it is stable lies between 847 and 930 C. The decagonal phase undergoes a eutectoid reaction to the three crystalline phases Al 3 Ni 2 , Al 3 Ni and Al 13 Fe 4 at 847 C. It melts peritectically at 930 C forming Al 13 Fe 4 , Al 3 Ni 2 and a liquid. The investigations in the Al-Cu-Ru system concentrated on the phase equilibria between the icosahedral phase and its neighbouring phases in a temperature range between 600 and 1000 C. The icosahedral phase was observed in the whole temperature range. The investigated stoichiometric area extends down to Al contents of 45%, which allows the fields of existence to be determined for the ternary phases α-AlCuRu, the icosahedral phase and Al 7 Cu 2 Ru. Binary phases were determined down to the upper (high Al content) border of AlRu. No hitherto unknown phase was observed in the investigated area. Rietveld analyses were carried out on α-AlCuRu and Al 7 Cu 2 Ru showing some discrepancies from the α-AlMnSi structure taken as a base for α-AlCuRu and confirming the Al 7 Cu 2 Fe structure for Al 7 Cu 2 Ru. (orig.)

Grindability of cast Ti-Cu alloys.

Science.gov (United States)

Kikuchi, Masafumi; Takada, Yukyo; Kiyosue, Seigo; Yoda, Masanobu; Woldu, Margaret; Cai, Zhuo; Okuno, Osamu; Okabe, Toru

2003-07-01

The purpose of the present study was to evaluate the grindability of a series of cast Ti-Cu alloys in order to develop a titanium alloy with better grindability than commercially pure titanium (CP Ti), which is considered to be one of the most difficult metals to machine. Experimental Ti-Cu alloys (0.5, 1.0, 2.0, 5.0, and 10.0 mass% Cu) were made in an argon-arc melting furnace. Each alloy was cast into a magnesia mold using a centrifugal casting machine. Cast alloy slabs (3.5 mm x 8.5 mm x 30.5 mm), from which the hardened surface layer (250 microm) was removed, were ground using a SiC abrasive wheel on an electric handpiece at four circumferential speeds (500, 750, 1000, or 1250 m/min) at 0.98 N (100 gf). Grindability was evaluated by measuring the amount of metal volume removed after grinding for 1min. Data were compared to those for CP Ti and Ti-6Al-4V. For all speeds, Ti-10% Cu alloy exhibited the highest grindability. For the Ti-Cu alloys with a Cu content of 2% or less, the highest grindability corresponded to an intermediate speed. It was observed that the grindability increased with an increase in the Cu concentration compared to CP Ti, particularly for the 5 or 10% Cu alloys at a circumferential speed of 1000 m/min or above. By alloying with copper, the cast titanium exhibited better grindability at high speed. The continuous precipitation of Ti(2)Cu among the alpha-matrix grains made this material less ductile and facilitated more effective grinding because small broken segments more readily formed.

Vacuum brazing of electroless Ni-P alloy-coated SiCp/Al composites using aluminum-based filler metal foil

Science.gov (United States)

Wang, Peng; Xu, Dongxia; Niu, Jitai

2016-12-01

Using rapidly cooled (Al-10Si-20Cu-0.05Ce)-1Ti (wt%) foil as filler metal, the research obtained high-performance joints of electroless Ni-P alloy-coated aluminum matrix composites with high SiC particle content (60 vol%, SiCp/Al-MMCs). The effect of brazing process on joint properties and the formation of Al-Ni and Al-Cu-Ni intermetallic compounds were investigated, respectively. Due to the presence of Ni-P alloy coating, the wettability of liquid filler metal on the composites was improved obviously and its contact angle was only 21°. The formation of Al3Ni2 and Al3(CuNi)2 intermetallic compounds indicated that well metallurgical bonding occurred along the 6063Al matrix alloy/Ni-P alloy layer/filler metal foil interfaces by mutual diffusion and dissolution. And the joint shear strength increased with increasing the brazing temperature from 838 to 843 K or prolonging the soaking time from 15 to 35 min, while it decreased a lot because of corrosion occurring in the 6063Al matrix at high brazing temperature of 848 K. Sound joints with maximum shear strength of 112.5 MPa were obtained at 843 K for soaking time of 35 min. In this research, the beneficial effect of surface metallization by Ni-P alloy deposits on improving wettability on SiCp/Al-MMCs was demonstrated, and capable welding parameters were broadened as well.

[Effect of heat treatment on the structure of a Cu-Zn-Al-Ni system dental alloy].

Science.gov (United States)

Guastaldi, A C; Adorno, A T; Beatrice, C R; Mondelli, J; Ishikiriama, A; Lacefield, W

1990-01-01

This article characterizes the structural phases present in the copper-based metallic alloy system "Cu-Zn-Al-Ni" developed for dental use, and relates those phases to other properties. The characterization was obtained after casting (using the lost wax process), and after heat treatment. In order to obtain better corrosion resistance by changing the microstructure, the castings were submitted to 30, 45 and 60 minutes of heat treatment at the following temperatures: 750 degrees C, 800 degrees C, and 850 degrees C. The various phases were analyzed using X-ray diffraction and scanning electron microscopy (SEM). The results after heat treatment showed a phase (probably Cu3Al), that could be responsible for the improvement in the alloy's resistance to corrosion as compared to the as-cast structure.

Microstructure, texture and magnetic properties of Ni-Cu-W substrates for coated conductors

DEFF Research Database (Denmark)

Wulff, Anders Christian; Mishin, Oleg; Andersen, Niels Hessel

2013-01-01

concentrations of copper, increasing the Cu-content to 10 at% and 15 at% leads to increased frequencies of annealing twins in the cube-textured matrix. It is suggested that the (Ni 95W5)100-xCux alloy with x=5 at% Cu may be a good candidate material for using as a substrate for coated conductors. © 2012 Elsevier...

Electric resistivity and thermoelectricity of Ni-Nb-Zr and Ni-Nb-Zr-H glassy alloys

Science.gov (United States)

Fukuhara, Mikio; Inoue, Akihisa

2010-09-01

Electric resistivity ρ and thermoelectric power S of Ni 36Nb 24Zr 40 and (Ni 0.36Nb 0.24Zr 0.4) 90H 10 glassy alloys were investigated in temperature region between 1.5 and 300 K. After resistivity curves of both alloys increase gradually with decreasing temperature down to around 6 K, they dropped suddenly and then reached zero resistivity at 2.1 K, leading to superconductivity. Linear curve with negative TCR of ρ vs T2 and slight increase of S/ T in temperature region down to around 6 K clearly reveal Fermi-liquid phenomenon in electronic state for both alloys independent of hydrogen content.

Electric resistivity and thermoelectricity of Ni-Nb-Zr and Ni-Nb-Zr-H glassy alloys

International Nuclear Information System (INIS)

Fukuhara, Mikio; Inoue, Akihisa

2010-01-01

Electric resistivity ρ and thermoelectric power S of Ni 36 Nb 24 Zr 40 and (Ni 0.36 Nb 0.24 Zr 0.4 ) 90 H 10 glassy alloys were investigated in temperature region between 1.5 and 300 K. After resistivity curves of both alloys increase gradually with decreasing temperature down to around 6 K, they dropped suddenly and then reached zero resistivity at 2.1 K, leading to superconductivity. Linear curve with negative TCR of ρ vs T 2 and slight increase of S/T in temperature region down to around 6 K clearly reveal Fermi-liquid phenomenon in electronic state for both alloys independent of hydrogen content.

Ground-state properties of ordered, partially ordered, and random Cu-Au and Ni-Pt alloys

DEFF Research Database (Denmark)

Ruban, Andrei; Abrikosov, I. A.; Skriver, Hans Lomholt

1995-01-01

We have studied the ground-state properties of ordered, partially ordered, and random Cu-Au and Ni-Pt alloys at the stoichiometric 1/4, 1/2, and 3/4 compositions in the framework of the multisublattice single-site (SS) coherent potential approximation (CPA). Charge-transfer effects in the random ...... for the ordered alloys are in good agreement with experimental data. For all the alloys the calculated ordering energy and the equilibrium lattices parameters are found to be almost exact quadratic functions of the long-range-order parameter....... and the partially ordered alloys are included in the screened impurity model. The prefactor in the Madelung energy is determined by the requirement that the total energy obtained in direct SS CPA calculations should equal the total energy given by the Connolly-Williams expansion based on Green’s function...

Comparison of properties and microstructures of Tréfimétaux CuNiBe and Hycon 3HPTM before and after neutron irradiation

DEFF Research Database (Denmark)

Singh, B.N.; Edwards, D.J.; Eldrup, Morten Mostgaard

2000-01-01

The precipitation strengthened CuNiBe alloys are among the three candidate copper alloys that are being evaluated for application in the first wall, divertor, and limiter components of ITER. Generally, CuNiBe alloys have higher strength but poorerconductivity compared to CuCrZr and Cu-A1_2O_3...... alloys. Brush-Wellman Inc. has developed an improved version of their Hycon CuNiBe alloy that has higher conductivity while maintaining a reasonable level of strength. In the present work we have investigatedthe physical and mechanical properties of the Hycon 3HPTM alloy both before and after neutron...

STUDY OF MICROSTRUCTURE, HARDNESS AND WEAR PROPERTIES OF SAND CAST Cu-4Ni-6Sn BRONZE ALLOY

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S. ILANGOVAN

2015-04-01

Full Text Available An alloy of Cu-4Ni-6Sn was cast in the sand moulds. The cast rods were homogenized, solution heat treated and aged for different periods of time. The specimens were prepared from the rods to study the microstructure, microhardness and wear properties. It was found that the aging process increases the hardness of the alloy significantly. It was due to the change in the microstructure of the alloy. Further, spinodal decomposition and the ordering reaction take place during the aging treatment. Specific wear rate was found to decrease with the hardness of the alloy. Coefficient of friction remains constant and is not affected by the aging process.

Cube Texture Formation of Cu-33at.%Ni Alloy Substrates and CeO₂ Buffer Layer for YBCO Coated Conductors

DEFF Research Database (Denmark)

Tian, Hui; Li, Suo Hong; Ru, Liang Ya

2014-01-01

Cube texture formation of Cu-33 at.%Ni alloy substartes and CeO2 buffer layer prepared by chemical solution deposition on the textured substrate were investigated by electron back scattered diffraction (EBSD) and XRD technics systematically. The results shown that a strong cube textured Cu-33at...

The kinetics of hydrogen absorption/desorption within nanostructured composite Ni79.1Co18.6Cu2.3 alloy using resistometry

International Nuclear Information System (INIS)

Spasojević, M.; Maričić, A.; Ribić Zelenović, L.; Krstajić, N.; Spasojević, P.

2013-01-01

Highlights: ► Nanostructured Ni 79.1 Co 18.6 Cu 2.3 powder was obtained by electrochemical deposition. ► Correlation observed between electrical conductivity and absorbed hydrogen amount. ► Hydrogen absorption/desorption mechanism was determined. - Abstract: Ni 79.1 Co 18.6 Cu 2.3 powder was obtained by electrochemical deposition from an ammonium sulfate bath. The structure and surface morphology of the powder were detected by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The electrochemically obtained Ni 79.1 Co 18.6 Cu 2.3 alloy contained an amorphous phase and nanocrystals with an average size of 6.8 nm of FCC phase of the solid solution of cobalt and copper in nickel. Nanocrystals were characterized by a high average microstrain value and high minimum density of chaotically distributed dislocations. X-ray analysis also showed that powder hydrogenation at an elevated temperature of up to 200 °C did not change unit cell parameters and mean crystallite size value. SEM images show the formation of two shapes of powder particles: large cauliflower-like particles and small dendritic ones. Powder pressing at 10 MPa and at 25 °C gave samples that were analyzed for hydrogen absorption/desorption within the temperature range of 160–200 °C. Changes in electrical resistivity during absorption/desorption were monitored. The reciprocal value of resistivity (electrical conductivity) was found to increase linearly with increasing amount of absorbed hydrogen. The experimental results were used to propose an absorption/desorption mechanism. The adsorbed hydrogen molecule dissociates on alloy surface, forming adsorbed atoms. Adatoms penetrate and diffuse into the bulk of the alloy, simultaneously donating their electrons to the conduction band of the alloy. The increase in the concentration of free electrons induces a decrease in electrical resistivity. The overall absorption rate during initial absorption is determined by the

Air oxidation of Zr65Cu17.5Ni10Al7.5 in its amorphous and supercooled liquid states, studied by thermogravimetric analysis

International Nuclear Information System (INIS)

Dhawan, A.; Sharma, S.K.; Raetzke, K.; Faupel, F.

2003-01-01

The oxidation behaviour of the bulk amorphous alloy Zr 65 Cu 17.5 Ni 10 Al 7.5 was studied in air at various temperatures in the temperature range 591-732 K using a thermogravimetric analyser (TGA). The oxidation kinetics of the alloy obeys the parabolic rate law showing two different linear regions (in the plots of mass gain versus square root of oxidation time) which are attributed to the amorphous and the supercooled liquid states of the alloy. The value of the activation energy Q for the amorphous state as calculated from the temperature dependence of the rate constants is found to be 1.80±0.1 eV and the corresponding value obtained for the supercooled liquid state is 1.20±0.1 eV. It is suggested that the rate controlling process during oxidation of the amorphous state is the back-diffusion of Ni, and possibly Cu also, while the oxidation in the supercooled liquid state is dominated by the inward diffusion of oxygen. (copyright 2003 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Thermophysical Properties of Cold and Vacuum Plasma Sprayed Cu-Cr-X Alloys, NiAl and NiCrAlY Coatings. Part 1; Electrical and Thermal Conductivity, Thermal Diffusivity, and Total Hemispherical Emissivity

Science.gov (United States)

Raj, S. V.

2017-01-01

This two-part paper reports the thermophysical properties of several cold and vacuum plasma sprayed monolithic Cu and Ni-based alloy coatings. Part I presents the electrical and thermal conductivity, thermal diffusivity, and total hemispherical emissivity data while Part II reports the specific heat capacity data for these coatings. Metallic copper alloys, stoichiometric NiAl and NiCrAlY coatings were fabricated by either the cold sprayed or the vacuum plasma spray deposition processes for thermal property measurements between 77 and 1223 K. The temperature dependencies of the thermal conductivities, thermal diffusivities, electrical conductivities and total hemispherical emissivities of these cold and vacuum sprayed monolithic coatings are reported in this paper. The electrical and thermal conductivity data correlate reasonably well for Cu-8%Cr-1%Al, Cu-23%Cr-5%Al and NiAl in accordance with the Wiedemann-Franz (WF) law although a better fit is obtained using the Smith-Palmer relationship. The Lorentz numbers determined from the WF law are close to the theoretical value.

Sintered Fe-Ni-Cu-Sn-C Alloys Made of Ball-Milled Powders

Directory of Open Access Journals (Sweden)

Romański A.

2014-10-01

Full Text Available The main objective of this paper was to perform sinterability studies of ball-milled Fe-12%Ni-6.4%Cu-1.6%Sn-0.6%C powders. A mixture of precisely weighed amounts of elemental iron, nickel and graphite, and pre-alloyed 80/20 bronze powders was ball-milled for 8, 30 and 120 hours. After cold-pressing at 400 MPa the specimens were sintered at 900oC for 30 minutes in a reducing atmosphere and subsequently tested for density and hardness as well as subjected to structural studies using scanning electron microscopy (SEM and X-ray diffraction (XRD analysis.

Effects of silicon and thermo-mechanical process on microstructure and properties of Cu–10Ni–3Al–0.8Si alloy

International Nuclear Information System (INIS)

Shen, Leinuo; Li, Zhou; Zhang, Zheming; Dong, Qiyi; Xiao, Zhu; Lei, Qian; Qiu, Wenting

2014-01-01

Highlights: • Cu–10Ni–3Al–0.8Si alloy with ultra-high strength was designed. • The addition of silicon hindered the precipitation of large NiAl phase. • Tensile strength and electrical conductivity were 1180 MPa and 18.1% IACS. • Nano-scale Ni 2 Si and Ni 3 Al improved the strength and electrical conductivity. - Abstract: Cu–10Ni–3Al–0.8Si alloy with ultra-high strength was designed and its microstructure was studied using optical microscopy, scanning electron microscopy, transmission electron microscopy. The alloy went through a set of thermo-mechanical process: solution treated at 950 °C for 4 h, then cold-rolled by 50% and aged at 450 °C for 8 h, followed by 60% cold-rolling and aging at 450 °C for 8 h. After these treatment, the tensile strength was 1180 MPa, yield strength was 1133 MPa and electrical conductivity was 18.1% IACS, respectively. The comprehensive properties, especially the electrical conductivity of the designed alloy, were much higher than those of traditional Cu–Ni–Al alloys. The addition of silicon in the designed alloy hindered the precipitation of large-scale NiAl phase and improved the strength of the alloy. The orientation relationships between δ-Ni 2 Si, Ni 3 Al precipitates and copper matrix were: [001] Cu ‖[001] Ni 3 Al ‖[001] δ ,(110) Cu ‖(110) Ni 3 Al ‖(010) δ ,(11 ¯ 0) Cu ‖ (11 ¯ 0) Ni 3 Al ||(100) δ , respectively

Comparative analysis of Nb and Ti addition in the Cu-11,8%wt.Al-0,5%wt.Be e Cu-11,8%wt.Al-3,0%wt.Ni shape memory alloy; Analise comparativa da adicao de NB e TI nas ligas Cu-11,8Al-0,5Be e Cu-11,8Al-3,0Ni passiveis do efeito memoria de forma

Energy Technology Data Exchange (ETDEWEB)

Silva Junior, M.Q. da; Oliveira, G.D. de, E-mail: manoel.quirino@ufersa.edu.br [Universidade Federal Rural do Semi-Arido (UFERSA), Mossoro, RN (Brazil)

2014-07-01

The system of the Cu-Al alloys shape memory alloy have been the subject of many studies due to a wide range of possible applications and relatively low cost, and the chemical composition of the main factors that determine the properties of these properties. This work analyzed the influence of Nb and Ti elements in Cu-11,8Al-0,5Be and Cu-11,8Al-3,0Ni alloy. The alloys are obtained by melting and passed through homogenizing heat treatment followed by water quenching at 30°C. The samples were characterized by Microscopy Optical, X-ray Diffraction and Microhardness testing. The alloys showed fine precipitates of second phase homogeneously distributed in the matrix that provides improvement in the properties of these alloys. (author)

On the mechanical behavior of a cryomilled Al-Ti-Cu alloy

International Nuclear Information System (INIS)

Han, Bing Q.; Lavernia, Enrique J.; Mohamed, Farghalli A.

2003-01-01

The mechanical behavior of a cryomilled Al10Ti2Cu that was later extruded was investigated in compression. The data obtained show that the strength of the extruded alloy parallel to the extrusion axis is higher than that normal to the axis. Also, a comparison between the compression behavior of the alloy and its tensile behavior reveals that there is a small asymmetry of yield strength with respect to deformation mode. Examination of the microstructure of the cryomilled alloy by means of transmission electron microscopy (TEM) indicates the presence of two phases: approximately 90% nanostructured Al(Cu) phase containing a dispersion of Al 3 Ti and 10% coarse-grained Al(Cu) phase. TEM observations indicate that as a result of the extrusion process, the larger (softer) grains of the Al(Cu) phase experience severe deformation, resulting in the development of mechanical fibering. It is suggested that the presence of coarse-grained Al(Cu) 'islands' in the matrix of the nanostructured phase and their change during extrusion into elongated bands may be responsible for the anisotropy of the mechanical properties of the extruded cryomilled Al10Ti2Cu

Effects of Alloying Elements on Room and High Temperature Tensile Properties of Al-Si Cu-Mg Base Alloys =

Science.gov (United States)

Alyaldin, Loay

In recent years, aluminum and aluminum alloys have been widely used in automotive and aerospace industries. Among the most commonly used cast aluminum alloys are those belonging to the Al-Si system. Due to their mechanical properties, light weight, excellent castability and corrosion resistance, these alloys are primarily used in engineering and in automotive applications. The more aluminum is used in the production of a vehicle, the less the weight of the vehicle, and the less fuel it consumes, thereby reducing the amount of harmful emissions into the atmosphere. The principal alloying elements in Al-Si alloys, in addition to silicon, are magnesium and copper which, through the formation of Al2Cu and Mg2Si precipitates, improve the alloy strength via precipitation hardening following heat treatment. However, most Al-Si alloys are not suitable for high temperature applications because their tensile and fatigue strengths are not as high as desired in the temperature range 230-350°C, which are the temperatures that are often attained in automotive engine components under actual service conditions. The main challenge lies in the fact that the strength of heat-treatable cast aluminum alloys decreases at temperatures above 200°C. The strength of alloys under high temperature conditions is improved by obtaining a microstructure containing thermally stable and coarsening-resistant intermetallics, which may be achieved with the addition of Ni. Zr and Sc. Nickel leads to the formation of nickel aluminide Al3Ni and Al 9FeNi in the presence of iron, while zirconium forms Al3Zr. These intermetallics improve the high temperature strength of Al-Si alloys. Some interesting improvements have been achieved by modifying the composition of the base alloy with additions of Mn, resulting in an increase in strength and ductility at both room and high temperatures. Al-Si-Cu-Mg alloys such as the 354 (Al-9wt%Si-1.8wt%Cu-0.5wt%Mg) alloys show a greater response to heat treatment as a

L10 ordered structures in Al-Cu-(Mg alloys at the early stages of elevated temperature aging

Directory of Open Access Journals (Sweden)

Fuzhong, Xia

2016-09-01

Full Text Available This study concerns the precipitation structures of Al-3Cu and Al-3Cu-1.78Mg (wt. % alloys at the early stages of elevated temperature aging. The Al-3Cu and Al-3Cu-1.78 Mg alloys were solution treated at 540 °C and 500 °C for 2 h, respectively, and then aged at 190 °C for 2 min. The precipitation structures in aged Al-3Cu-(1.78Mg alloys were characterized by Transmission Electron Microscopy (TEM and High Resolution Transmission Electron Microscopy (HTREM. 001 zone axis Selected area electron diffraction patterns indicate that L10 ordered structures are formed in the two aged alloys. HRTEM experiments reveal the partial dislocations on the interfaces of L10 ordered structures. From comparing experimental results with that in the literature, it is concluded that the L10 ordered structures in aged Al-3Cu alloy consist of Al and Cu atoms, and they are comprised by Al, Cu and Mg atoms together in the aged Al-3Cu-1.78Mg alloy. On the basis of precipitate growing thermodynamics, it is thought the L10 ordered structures act as nuclei for GP zones in Al-Cu-(Mg alloys during aging.En este trabajo se estudian las estructuras de precipitación en Al-3Cu y Al-3Cu-1,78Mg (% en peso en los estados iniciales de envejecimiento a temperatura elevada. Las aleaciones Al-3Cu y Al-3Cu-1.78 Mg fueron sometidas a un tratamiento térmico de solución de 2 h a 540 °C y 500 °C, respectivamente, y posteriormente envejecidas 2 min a 190 °C. Las estructuras de precipitación en Al-3Cu-(1.78Mg envejecido fueron caracterizadas por microscopía electrónica de transmisión (TEM y por microscopía electrónica de transmisión de alta resolución (HTREM. Los diagramas de difracción de electrones de área seleccionada indican que se forman estructuras ordenadas L10 en las dos aleaciones envejecidas. Experimentos de HRTEM revelan la presencia de dislocaciones parciales en las intercaras de las estructuras L10 ordenadas. Comparando estos resultados experimentales con la

Effect of minor elements on microstructure evolution in Ni alloys irradiated with neutrons

International Nuclear Information System (INIS)

Xu, Q.; Yoshiie, T.

2001-01-01

The minor elements, Si (-5.81%), Cu (7.18%), Ge (14.76%) and Sn (74.08%) were chosen to investigate the effects of volume size factor as shown in the parentheses on void swelling in neutron irradiated Ni alloys. Neutron irradiation temperature and dose were changed widely from 473 K to 703 K, and 0.001 dpa to 1 dpa, respectively. Voids were observed by transmission electron microscopy (TEM) in Ni even after a very small irradiation dose of 0.026 dpa at 573 K. With increasing dose, the number density of voids was nearly constant while void size increased. The microstructure evolution in Ni-2 at%Cu and Ni-2 at%Ge alloys was similar to that in Ni. However, in Ni-2 at%Si and Ni-2 at%Sn alloys, no voids were observed by TEM even at 703 K to 1 dpa. The minor elements, Si and Sn, play an important role for the suppression of vacancy clusters. Vacancies are annihilated by mutual recombination with interstitials in Si and Sn added alloys. (orig.)

Hydrogen absorption in Mg1.95Ti0.05Ni0.95Cu0.05 alloy prepared with mechanical alloying and thermal treatment; Absorcion de hidrogeno en la aleacion Mg1.95Ti0.05Ni0.95Cu0.05 preparada por aleado mecanico y tratamiento termico

Energy Technology Data Exchange (ETDEWEB)

Martinez, Juan Bonifacio; Urena Nunez, Fernando [Instituto Nacional de Investigaciones Nucleares, Ocoyoacac, Estado de Mexico (Mexico)]. E-mail: juan.bonifacio@inin.gob.mx

2009-09-15

This work presents hydrogen absorption in quaternary alloy Mg1.95Ti0.05Ni0.95Cu0.05 obtained by the mechanical alloying method, followed by thermal treatment in ultra-high pure argon atmosphere. The composition of the phases, microstructure and morphology of ground powders and with thermal treatment were characterized by DRX, SEM/EDS and TEM. After 20 hours of mechanical grinding and recooked at 300 degrees Celsius/1h in argon atmosphere, the quaternary alloy has a Mg{sub 2}Ni crystalline hexagonal structure with a crystallite size under 10 nm. The absorption measurements were performed under a pressure of 0.2 to 1.2 MPa at a temperature of 200 degrees Celsius in a micro-reactor. The quantification of absorption-desorption of hydrogen in the intermetallic was conducted in a TGA-DSC simultaneous calorimeter. Metallic hydride-dehydride powder was characterized with SEM and XRD. [Spanish] En este trabajo se presenta la absorcion de hidrogeno en la aleacion cuaternaria Mg1.95Ti0.05Ni0.95Cu0.05 obtenida por el metodo de aleado mecanico, seguida de tratamiento termico en atmosfera de argon de ultra alta pureza. La composicion de las fases, microestructura y morfologia de los polvos molidos y con tratamiento termico fue caracterizada por DRX, SEM/EDS y TEM. Despues de 20 h de molienda mecanica con recocido a 300 grados Celsios/1h en atmosfera de argon, la aleacion cuaternaria tiene una estructura cristalina hexagonal Mg{sub 2}Ni con tamano de cristalito menor a 10 nm. Las mediciones de absorcion fueron realizadas bajo una presion de 0.2 a 1.2 MPa a una temperatura de 200 grados Celsios en un micro-reactor. La cuantificacion de absorcion-desorcion de hidrogeno en el intermetalico se realizo en un calorimetro simultaneo TGA-DSC. Se determino que la cantidad maxima absorbida de hidrogeno en la aleacion cuaternaria fue de 3.24% en peso cuando la presion fue de 0.8 MPa a dicha temperatura. Polvos metalicos hidrurados-deshidrurados se caracterizaron por SEM y XRD.

Tuning Low Cycle Fatigue Properties of Cu-Be-Co-Ni Alloy by Precipitation Design

Directory of Open Access Journals (Sweden)

Yanchuan Tang

2018-06-01

Full Text Available As material for key parts applied in the aerospace field, the Cu-Be-Co-Ni alloy sustains cyclic plastic deformation in service, resulting in the low cycle fatigue (LCF failure. The LCF behaviors are closely related to the precipitation states of the alloy, but the specific relevance is still unknown. To provide reasonable regulation of the LCF properties for various service conditions, the effect of precipitation states on the LCF behaviors of the alloy was investigated. It is found that the alloy composed fully of non-shearable γ′ precipitates has higher fatigue crack initiation resistance, resulting in a longer fatigue life under LCF process with low total strain amplitude. The alloy with fine shearable γ′I precipitates presents higher fatigue crack propagation resistance, leading to a longer fatigue life under LCF process with high total strain amplitude. The cyclic stress response behavior of the alloy depends on the competition between the kinematic hardening and isotropic softening. The fine shearable γ′I precipitates retard the decrease of effective stress during cyclic loading, causing cyclic hardening of the alloy. The present work would help to design reasonable precipitation states of the alloy for various cyclic loading conditions to guarantee its safety in service.

Influence of electroless coatings of Cu, Ni-P and Co-P on MmNi3.25Al0.35Mn0.25Co0.66 alloy used as anodes in Ni-MH batteries

International Nuclear Information System (INIS)

Raju, M.; Ananth, M.V.; Vijayaraghavan, L.

2009-01-01

Electroless coatings of Ni-P, Co-P and Cu were applied on the surface of non-stoichiometric MmNi 3.25 Al 0.35 Mn 0.25 Co 0.66 (Mm: misch metal) metal hydride alloy. Elemental analysis was made with Energy Dispersive X-ray Analysis (EDAX). The structural analysis of bare and coated alloys was done by X-ray diffraction (XRD) whereas surface morphology was examined with scanning electron microscope (SEM) and transmission electron microscope (TEM). The electrode characteristics inclusive of electrochemical capacity and cycle life were studied at C/5 rate. Superior performance is obtained with copper coated alloy. Microstructure observations indicate that the observed excellent performance could be attributed to uniform and efficient surface coverage with copper. Also, lanthanum surface enrichment in samples during Cu coating leads to improvement in performance. It is inferred from electro analytical investigations that copper coatings act as microcurrent collectors with alterations in hydrogen transport mechanism and facilitate charge transfer reaction on the alloy surface without altering battery properties. Moreover, supportive first time TEM evidence of existence of such copper nano current collectors (about 8 nm in diameter and length about 20 nm) is reported.

Wettability of zirconium diboride ceramics by Ag, Cu and their alloys with Zr

International Nuclear Information System (INIS)

Muolo, M.L.; Ferrera, E.; Novakovic, R.; Passerone, A.

2003-01-01

Sintered ZrB 2 ceramics, pure and with 4 wt.% Ni as sintering aid, have been tested in contact with liquid Ag, Cu, Ag-Cu and Ag-Cu-Zr. ''Pure'' ZrB 2 ceramics are wetted by Ag-Zr alloys, and ZrB 2 /Ni ceramics also by pure Cu. The wetting behaviour is briefly discussed in terms of existing wetting theories

Texture Formation of Electroplated Nickel and Nickel Alloy on Cu Substrate

International Nuclear Information System (INIS)

Lee, Hee Gyoun; Hong, Gye Won; Kim, Jae Geun; Lee, Sun Wang; Kim, Ho Jin

2006-01-01

Nickel and nickel-tungsten alloy were electroplated on a cold rolled and heat treated copper(Cu) substrate. 4 mm-thick high purity commercial grade Cu was rolled to various thicknesses of 50, 70, 100 and 150 micron. High reduction ratio of 30% was applied down to 150 micron. Rolled texture was converted into cube texture via high temperature heat treatment at 400-800 degrees C. Grain size of Cu was about 50 micron which is much smaller compared to >300 micron for the Cu prepared using smaller reduction pass of 5%. 1.5 km-long 150 micron Cu was fabricated with a rolling speed of 33 m/min and texture of Cu was uniform along length. Abnormal grain growth and non-cube texture appeared for the specimen anneal above 900 degrees C. 1-10 micron thick Ni and Ni-W film was electroplated onto an annealed cube-textured Cu or directly on a cold rolled Cu. Both specimens were annealed and the degree of texture was measured. For electroplating of Ni on annealed Cu, Ni layer duplicated the cube-texture of Cu substrate and the FWHM of in plane XRD measurement for annealed Cu layer and electroplated layer was 9.9 degree and 13.4 degree, respectively. But the FWHM of in plane XRD measurement of the specimen which electroplated Ni directly on cold rolled Cu was 8.6 degree, which is better texture than that of nickel electroplated on annealed Cu and it might be caused by the suppression of secondary recrystallization and abnormal grain growth of Cu at high temperature above 900 degrees C by electroplated nickel.

Effects of annealing on the microstructure and magnetic property of the mechanically alloyed FeSiBAlNiM (M=Co, Cu, Ag) amorphous high entropy alloys

Energy Technology Data Exchange (ETDEWEB)

Zhu, Xiaoxia; Zhou, Xuan; Yu, Shuaishuai; Wei, Congcong; Xu, Jing; Wang, Yan, E-mail: mse_wangy@ujn.edu.cn

2017-05-15

The effects of annealing treatment on the microstructure, thermal stability, and magnetic properties of the mechanical alloyed FeSiBAlNiM (M=Co, Cu, Ag) amorphous high entropy alloys (HEAs) have been investigated in this project. The simple crystallization products in FeSiBAlNi amorphous HEAs with Co and Ag addition reveal the high phase stability during heating process. At high annealing treatment, the crystallized HEAs possess the good semi-hard magnetic property. It can conclude that crystallization products containing proper FeSi-rich and FeB-rich phases are beneficial to improve the magnetic property. Annealing near the exothermic peak temperature presents the best enhancing effect on the semi-hard magnetic property of FeSiBAlNiCo. It performs both large saturated magnetization and remanence ratio of 13.0 emu/g and near 45%, which exhibit 465% and 105% enhancement compared with as-milled state, respectively. - Highlights: • Co, Cu, Ag additions affect crystallization behavior of FeSiBAlNi amorphous HEAs. • Crystallization products in FeSiBAlNi Co/Ag reveal high phase stability. • Proper FeSi-rich and FeB-rich phases are beneficial to improve magnetic property. • Annealing treatment improves semi-hard magnetic property compared to as-milled state. • Annealing near exothermic peak temperature shows best enhancing effect on magnetism.

Corrosion and wear protective composition modulated alloy coatings based on ternary Ni-P-X alloys

DEFF Research Database (Denmark)

Leisner, P.; Benzon, M. E.; Christoffersen, Lasse

1996-01-01

Scattered reporting in the litterature describes a number of ternary Ni-P-X alloyes (where X can be Co, Cr, Cu, Mo, Pd, Re or W) with promising corrosin and wear protective performance. Based on a systematic study of Ni-P-X alloys it is the intention to produce coatings with improved corrosion...... and wear performance compared with conventional coatings like electroless nickel, hard chromioum and anodised aluminium....

The effect of addition of various elements on properties of NiTi-based shape memory alloys for biomedical application

Science.gov (United States)

Kök, Mediha; Ateş, Gonca

2017-04-01

In biomedical applications, NiTi and NiTi-based alloys that show their shape memory effects at body temperature are preferred. In this study, the purpose is to produce NiTi and NiTi-based alloys with various chemical rates and electron concentrations and to examine their various physical properties. N45Ti55, Ni45Ti50Cr2.5Cu2.5, Ni48Ti51X (X=Mn, Sn, Co) alloys were produced in an arc melter furnace in this study. After the homogenization of these alloys, the martensitic phase transformation temperatures were determined with differential-scanner calorimeter. The transformation temperature was found to be below the 37 ° C (body temperature) in Ni45Ti50Cr2.5Cu2.5, Ni48Ti51X (X=Mn, Co) alloys; and the transformation temperature of the N45Ti55, Ni48Ti51Sn alloys was found to be over 37 ° C . Then, the micro and crystal structure analyses of the alloys were made, and it was determined that Ni45Ti50Cr2.5Cu2.5, Ni48Ti51X (X=Mn, Co) alloys, which were in austenite phase at room temperature, included B2 (NiTi) phase and Ti2Ni precipitation phase, and the alloys that were in the martensite phase at room temperature included B19ı (NiTi) phase and Ti2Ni phase. The common phase in both alloy groups is the Ti2Ni phase, and this type of phase is generally seen in NiTi alloys that are rich in titanium (Ti-rich).

An augmented space recursive method for the first principles study of concentration profiles at CuNi alloy surfaces

International Nuclear Information System (INIS)

Dasgupta, I.; Mookerjee, A.

1995-07-01

We present here a first principle method for the calculation of effective cluster interactions for semi-infinite solid alloys required for the study of surface segregation and surface ordering on disordered surfaces. Our method is based on the augmented space recursion coupled with the orbital peeling method of Burke in the framework of the TB-LMTO. Our study of surface segregation in CuNi alloys demonstrates strong copper segregation and a monotonic concentration profile throughout the concentration range. (author). 35 refs, 4 figs, 2 tabs

Thermal and mechanical properties of the Zr53Cu30Ni9Al8 based bulk metallic glass microalloyed with silicon

International Nuclear Information System (INIS)

Jang, Jason S.C.; Jian, S.R.; Chang, C.F.; Chang, L.J.; Huang, Y.C.; Li, T.H.; Huang, J.C.; Liu, C.T.

2009-01-01

The amorphous alloy rods of (Zr 53 Cu 30 Ni 9 Al 8 ) 100-x Si x (x = 0.25, 0.5, 0.75, 1) with a diameter of 2-6 mm were prepared by drop casting method in an Ar atmosphere. The thermal properties, including glass forming ability (GFA) and thermal stability during isothermal annealing of these amorphous alloys, and the mechanical properties have been systematic investigated by the combination of DSC, XRD, SEM, TEM, and compression test. The result of X-ray diffraction reveals that these entire (Zr 53 Cu 30 Ni 9 Al 8 ) 100-x Si x alloy rods exhibit a typical amorphous diffraction pattern with only a broad maximum around 2θ around 40 degree. Both T g (glass transition temperature) and T x (crystallization temperature) of these (Zr 53 Cu 30 Ni 9 Al 8 ) 100-x Si x alloys increase with the silicon addition. In addition, both the activation energy of crystallization and the incubation time of isothermal annealing these (Zr 53 Cu 30 Ni 9 Al 8 ) 100-x Si x amorphous alloys indicate that the (Zr 53 Cu 30 Ni 9 Al 8 ) 99.25 Si 0.75 alloy possesses the best thermal stability in the (Zr 53 Cu 30 Ni 9 Al 8 ) 100-x Si x alloy system. In parallel, the result of compression test shows that the yield strength increases with the addition of Si content and reaches to a maximum value about 1750 MPa with 3% plastic strain for the (Zr 53 Cu 30 Ni 9 Al 8 ) 99.25 Si 0.75 amorphous alloy.

Solution-Based Epitaxial Growth of Magnetically Responsive Cu@Ni Nanowires

KAUST Repository

Zhang, Shengmao; Zeng, Hua Chun

2010-01-01

An experiment was conducted to show the solution-based epitaxial growth of magnetically responsive Cu@Ni nanowires. The Ni-sheathed Cu nanowires were synthesized with a one-pot approach. 30 mL of high concentration NaOH, Cu(NO3)2. 3H2O, Cu(NO3)2. 3H2O and 0.07-0.30 mL of Ni(NO3)2. 6H 2O aqueous solutions were added into a plastic reactor with a capacity of 50.0 mL. A varying amount of ethylenediamine (EDA) and hydrazine were also added sequentially, followed by thorough mixing of all reagents. The dimension, morphology, and chemical composition of the products were examined with scanning electron microscopy with energy dispersive X-ray spectroscopy. The XPS analysis on the as formed Cu nanowires confirms that there is indeed no nickel inclusion in the nanowires prior to the formation of nickel overcoat, which rules out the possibility of Cu-Ni alloy formation.

Solution-Based Epitaxial Growth of Magnetically Responsive Cu@Ni Nanowires

KAUST Repository

Zhang, Shengmao

2010-02-23

An experiment was conducted to show the solution-based epitaxial growth of magnetically responsive Cu@Ni nanowires. The Ni-sheathed Cu nanowires were synthesized with a one-pot approach. 30 mL of high concentration NaOH, Cu(NO3)2. 3H2O, Cu(NO3)2. 3H2O and 0.07-0.30 mL of Ni(NO3)2. 6H 2O aqueous solutions were added into a plastic reactor with a capacity of 50.0 mL. A varying amount of ethylenediamine (EDA) and hydrazine were also added sequentially, followed by thorough mixing of all reagents. The dimension, morphology, and chemical composition of the products were examined with scanning electron microscopy with energy dispersive X-ray spectroscopy. The XPS analysis on the as formed Cu nanowires confirms that there is indeed no nickel inclusion in the nanowires prior to the formation of nickel overcoat, which rules out the possibility of Cu-Ni alloy formation.

Characterization of uniaxial fatigue behavior of precipitate strengthened Cu-Ni-Si alloy (SICLANIC(TM

Directory of Open Access Journals (Sweden)

B. Saadouki

2018-01-01

Full Text Available Fatigue tests were conducted on cylindrical bars specimens to understand the fatigue behavior of SICLANIC. Although it displays good resistance in monotonic tension, this material weakens and shows a softening in repeated solicitation. This has been verified through a SEM observation, the Cu-Ni-Si alloy presents transgranular failure by cleavage. The MansonCoffin diagram exhibited the plastic deformation accommodation. The plastic deformation becomes periodic and decreases progressively as the cycle number increases. The approximations of Manson Coffin give fatigue parameters values which are in good agreement with the experience

Investigation on corrosion and wear behaviors of nanoparticles reinforced Ni-based composite alloying layer

International Nuclear Information System (INIS)

Xu Jiang; Tao Jie; Jiang Shuyun; Xu Zhong

2008-01-01

In order to investigate the role of amorphous SiO 2 particles in corrosion and wear resistance of Ni-based metal matrix composite alloying layer, the amorphous nano-SiO 2 particles reinforced Ni-based composite alloying layer has been prepared by double glow plasma alloying on AISI 316L stainless steel surface, where Ni/amorphous nano-SiO 2 was firstly predeposited by brush plating. The composition and microstructure of the nano-SiO 2 particles reinforced Ni-based composite alloying layer were analyzed by using SEM, TEM and XRD. The results indicated that the composite alloying layer consisted of γ-phase and amorphous nano-SiO 2 particles, and under alloying temperature (1000 deg. C) condition, the nano-SiO 2 particles were uniformly distributed in the alloying layer and still kept the amorphous structure. The corrosion resistance of composite alloying layer was investigated by an electrochemical method in 3.5%NaCl solution. Compared with single alloying layer, the amorphous nano-SiO 2 particles slightly decreased the corrosion resistance of the Ni-Cr-Mo-Cu alloying layer. X-ray photoelectron spectroscopy (XPS) revealed that the passive films formed on the composite alloying consisted of Cr 2 O 3 , MoO 3 , SiO 2 and metallic Ni and Mo. The dry wear test results showed that the composite alloying layer had excellent friction-reduced property, and the wear weight loss of composite alloying layer was less than 60% of that of Ni-Cr-Mo-Cu alloying layer

DO22-(Cu,Ni)3Sn intermetallic compound nanolayer formed in Cu/Sn-nanolayer/Ni structures

International Nuclear Information System (INIS)

Liu Lilin; Huang, Haiyou; Fu Ran; Liu Deming; Zhang Tongyi

2009-01-01

The present work conducts crystal characterization by High Resolution Transmission Electron Microscopy (HRTEM) on Cu/Sn-nanolayer/Ni sandwich structures associated with the use of Energy Dispersive X-ray (EDX) analysis. The results show that DO 22 -(Cu,Ni) 3 Sn intermetallic compound (IMC) ordered structure is formed in the sandwich structures at the as-electrodeposited state. The formed DO 22 -(Cu,Ni) 3 Sn IMC is a homogeneous layer with a thickness about 10 nm. The DO 22 -(Cu,Ni) 3 Sn IMC nanolayer is stable during annealing at 250 deg. C for 810 min. The formation and stabilization of the metastable DO 22 -(Cu,Ni) 3 Sn IMC nanolayer are attributed to the less strain energy induced by lattice mismatch between the DO 22 IMC and fcc Cu crystals in comparison with that between the equilibrium DO 3 IMC and fcc Cu crystals.

Magnetic behavior of NiCu nanowire arrays: Compositional, geometry and temperature dependence

International Nuclear Information System (INIS)

Palmero, E. M.; Bran, C.; Real, R. P. del; Vázquez, M.; Magén, C.

2014-01-01

Arrays of Ni 100−x Cu x nanowires ranging in composition 0 ≤ x ≤ 75, diameter from 35 to 80 nm, and length from 150 nm to 28 μm have been fabricated by electrochemical co-deposition of Ni and Cu into self-ordered anodic aluminum oxide membranes. As determined by X-ray diffraction and Transmission Electron Microscopy, the crystalline structure shows fcc cubic symmetry with [111] preferred texture and preferential Ni or Cu lattice depending on the composition. Their magnetic properties such as coercivity and squareness have been determined as a function of composition and geometry in a Vibrating Sample Magnetometer in the temperature range from 10 to 290 K for applied magnetic fields parallel and perpendicular to the nanowires axis. Addition of Cu into the NiCu alloy up to 50% enhances both parallel coercivity and squareness. For the higher Cu content, these properties decrease and the magnetization easy axis becomes oriented perpendicular to the wires. In addition, coercivity and squareness increase by decreasing the diameter of nanowires which is ascribed to the increase of shape anisotropy. The temperature dependent measurements reflect a complex behavior of the magnetic anisotropy as a result of energy contributions with different evolution with temperature.

Microstructural and electrical investigation of Cu-Ni-Cr alloys obtained by powder metallurgy method

International Nuclear Information System (INIS)

Carrio, Juan A.G.; Carvalhal, M.A.; Ayabe, L.M.; Monteiro, W.A.

2009-01-01

The aim of this work, using the powder metallurgy process, is to synthesize metallic alloys with high mechanical strength and high electric conductivity, after melting optimizing and thermal treatments. The Cu-Ni-Cr (wt%) alloys are characterized in their mechanical and electrical properties as well as the obtained microstructure. Through the process of powder metallurgy, contacts and structural parts can be obtained. The alloys elements are added to copper with the intention to improve their strength, ductility and thermal stability, without causing considerable damages in their form, electrical and thermal conductivity, and corrosion resistance. The metallic powders were mixed for a suitable time and then they were pressed in a cold uniaxial pressing (1000 kPa). Afterwards, the specimens were sintered in temperatures varying from 700 up to 800 deg C under vacuum. At last, the samples were homogenized at 550 deg C under vacuum, for special times. The comparative analysis is based on the sintered density, densification parameter, hardness, macrostructures and microstructures of the samples. The alloys were characterized by optical microscopy, X-rays powder diffraction, electrical conductivity and Vickers hardness. (author)

Interfacial Stresses and the Anomalous Character of Thermoelastic-Deformation Curves of a Cu-Al-Ni Shape-Memory Alloy

Science.gov (United States)

Malygin, G. A.; Nikolaev, V. I.; Pulnev, S. A.; Chikiryaka, A. V.

2017-12-01

Thermoelastic-deformation curves of a single-crystalline Cu-13.5 wt % Al-4.0 wt % Ni shapememory (SM) alloy have been studied. Cyclic temperature variation in a 300-450 K interval revealed an anomalous character of thermoelastic hysteresis loops with regions of accelerated straining at both heating and cooling stages. The observed phenomenon can be used for increasing the response speed of SM-alloy based drive and sensor devices. Analysis of this phenomenon in the framework of the theory of diffuse martensitic transformations showed that the anomalous character of thermoelastic hysteresis loops may be related to the influence of interfacial stresses on the dynamics of martensitic transformations in these SM alloys.

Fabrication of a micrometer Ni–Cu alloy column coupled with a Cu micro-column for thermal measurement

International Nuclear Information System (INIS)

Lin, J C; Chang, T K; Yang, J H; Jeng, J H; Lee, D L; Jiang, S B

2009-01-01

Micrometer Ni–Cu alloy columns have been fabricated by the micro-anode-guided electroplating (MAGE) process in the citrate bath. The surface morphology and chemical composition of the micro-columns were determined by copper concentration in the bath and by the electrical bias of MAGE. When fabricated in a bath of dilute copper (i.e. 4 mM) at lower voltages (e.g. 3.8 and 4.0 V), the alloy micro-columns revealed uniform diameter and smooth appearance. The alloy composition demonstrated an increase in the wt% ratio of Ni/Cu from 75/25, 80/20, 83/17 to 87/13 with increasing electrical bias from 3.8, 4.0, 4.2 to 4.4 V. However, it decreases from 75/25, 57/43 to 47/53 with increasing copper concentration from 4, 8 to 12 mM in the bath. Citrate plays a role in forming complexes with nickel and copper at similar reduction potentials, thus reducing simultaneously to Ni–Cu alloy. The mechanism for fabricating alloy micro-columns could be delineated on the basis of cathodic polarization of the complexes. A couple of micro-columns were fabricated using MAGE in constructing a pure copper micro-column on the top of a Ni/Cu (at 47/53) alloy micro-column. This micro-thermocouple provides a satisfactory measurement with good sensitivity and precision

Magnetostatic coupling of 90 domain walls in FeNi/Cu/Co trilayers

Energy Technology Data Exchange (ETDEWEB)

Kurde, Julia; Miguel, Jorge; Kuch, Wolfgang [Freie Universitaet, Berlin (Germany); Bayer, Daniela; Aeschlimann, Martin [Technische Universitaet, Kaiserslautern (Germany); Sanchez-Barriga, Jaime; Kronast, Florian; Duerr, Herrmann A. [Helmholtz-Zentrum Berlin fuer Materialien und Energie (Germany)

2011-07-01

The magnetic interlayer coupling of FeNi/Cu/Co trilayered microstructures has been studied by means of X-ray magnetic circular dichroism in combination with photoelectron emission microscopy (XMCD-PEEM). We find that a parallel coupling between magnetic domains coexists with a non-parallel coupling between magnetic domain walls of each ferromagnetic layer. We attribute the non-parallel coupling of the two magnetic layers to local magnetic stray fields arising at domain walls in the magnetically harder Co layer. In the magnetically softer FeNi layer non-ordinary domain walls such as 270 and 90 domain walls with overshoot of the magnetization either inwards or outwards relative to the turning direction of the Co magnetization are identified. Micromagnetic simulations reveal that in the absence of magnetocrystalline anisotropy, both types of overshooting domain walls are energetically equivalent. However, if a uniaxial in-plane anisotropy is present, the relative orientation of the domain walls with respect to the anisotropy axis determines which of these domain walls is energetically favorable.

Crystallization behavior of Zr62Al8Ni13Cu17 Metallic Glass

Directory of Open Access Journals (Sweden)

Jo Mi Sun

2017-06-01

Full Text Available The crystallization behavior has been studied in Zr62Al8Ni13Cu17 metallic glass alloy. The Zr62Al8Ni13Cu17 metallic glass crystallized through two steps. The fcc Zr2Ni phase transformed from the amorphous matrix during first crystallization and then the Zr2Ni and residual amorphous matrix transformed into a mixture of tetragonal Zr2Cu and hexagonal Zr6Al2Ni phases. Johnson-Mehl-Avrami analysis of isothermal transformation data suggested that the formation of crystalline phase is primary crystallization by diffusion-controlled growth.

Simulation of the microstructural evolution under irradiation of dilute Fe-CuNiMnSi alloys by atomic kinetic monte Carlo model based on ab initio data

International Nuclear Information System (INIS)

Vincent, E.; Domain, C.; Vincent, E.; Becquart, C.S.

2008-01-01

Full text of publication follows. The embrittlement and the hardening of pressure vessel steels under radiation has been correlated with the presence solutes such as Cu, Ni, Mn and Si. Indeed it has been observed that under irradiation, these solutes tend to gather to form more or less dilute clusters. The interactions of these solutes with radiation induced point defects thus need to be characterised properly in order to understand the elementary mechanisms behind the formation of these clusters. Ab initio calculations based on the density functional theory have been performed to determine the interactions of point defects (vacancies as well as interstitials) with solute atoms in dilute FeX alloys (X Cu, Mn, Ni or Si) in order to build a database used to parameterize an atomic kinetic Monte Carlo model. The model has been applied to simulate thermal ageing as well as irradiation conditions in dilute Fe-CuNiMnSi alloys. Results obtained with this model will be presented. (authors)

Transformation behavior and shape memory properties of Ti50Ni15Pd25Cu10 high temperature shape memory alloy at various aging temperatures

International Nuclear Information System (INIS)

Rehman, Saif ur; Khan, Mushtaq; Nusair Khan, A.; Ali, Liaqat; Zaman, Sabah; Waseem, Muhammad; Ali, Liaqat; Jaffery, Syed Husain Imran

2014-01-01

This research presents an insight into the effect of various aging temperatures on the microstructure, hardness, phase transformation behavior and shape memory properties of Ti 50 Ni 15 Pd 25 Cu 10 high temperature shape memory alloy. The aging temperature was varied from 350 °C to 750 °C, whereas the shape memory properties were evaluated at 100–500 MPa. It was observed that the mentioned properties were strongly dependent on the aging temperatures. Based on the results obtained from scanning electron microscopy, X-ray diffractometry, microhardness testing, differential scanning calorimetry and thermomechanical testing, the aging temperatures can be divided into three ranges. At low aging temperatures (350 °C and below), the properties of the alloy remained the same as were found for solution treated sample, however at intermediate aging temperatures (400–600 °C) the properties of the alloy were changed significantly. Due to the formation of precipitates, the hardness was increased, whereas the phase transformation temperatures and work output were decreased considerably. The recovery ratio was found to be improved for intermediate aging temperatures. At high aging temperatures (650 °C and above), the hardness was decreased and the phase transformation temperatures were increased. Phase transformation temperature at the aging temperature of 750 °C was found to be increased significantly as compared to solution treated sample

Glass-forming ability and crystallization behavior of some binary and ternary Ni-based glassy alloys

International Nuclear Information System (INIS)

Louzguine-Luzgin, Dmitri V.; Louzguina-Luzgina, Larissa V.; Xie Guoqiang; Li Song; Zhang Wei; Inoue, Akihisa

2008-01-01

The purpose of the current paper is to study the influence of Ti, V, Nb, Al, Sn and Pd additions on the glass-forming ability, formation of a supercooled liquid region and a devitrification process of some Ni-Zr glassy alloys as well as to compare the results with those obtained for similar Cu-based alloys studied earlier. The Ni-based glassy alloys were investigated by using X-ray diffraction, differential scanning and isothermal calorimetries. Although the studied Ni-based alloys showed high values of the reduced glass-transition temperature of about 0.6, their glass-forming ability is quite low. This fact may be explained by low stability of the supercooled liquid against crystallization and formation of the equilibrium intermetallic compounds with a high growth rate compared to those observed in similar Cu-based alloys studied earlier. Relatively low thermal conductivity of Ni-based alloys is also found to be another factor limiting their glass-forming ability

Instability of TiC and TiAl3 compounds in Al-10Mg and Al-5Cu alloys by addition of Al-Ti-C master alloy

Institute of Scientific and Technical Information of China (English)

无

2006-01-01

The performance of Al-Ti-C master alloy in refining Al-10Mg and A1-5Cu alloys was studied by using electron probe micro-analyzer (EPMA) and X-ray diffractometer (XRD) analysis.The results indicate that there are obvious fading phenomena in both Al-10Mg and Al-5Cu alloys with the addition of Al-5Ti-0.4C refiner which contains TiC and TiAl3 compounds.Mg element has no influence on the stability of TiC and TiAl3, while TiC particles in Al-10Mg alloy react with Al to form Al4C3 particles, resulting in the refinement fading.However, TiC particles are relatively stable in Al-5Cu alloy, while TiAl3 phase reacts with Al2Cu to produce a new phase Ti(Al, Cu)2, which is responsible for the refinement fading in Al-5Cu alloy.These indicate that the refinement fading will not occur only when both the TiC particles and TiAl3 compound of Al-Ti-C refiner are stable in Al alloys.

Mechanical Deformation Behavior of Sn-Ag-Cu Solders with Minor Addition of 0.05 wt.% Ni

Science.gov (United States)

Hammad, A. E.; El-Taher, A. M.

2014-11-01

The aim of the present work is to develop a comparative evaluation of the microstructural and mechanical deformation behavior of Sn-Ag-Cu (SAC) solders with the minor addition of 0.05 wt.% Ni. Test results showed that, by adding 0.05Ni element into SAC solders, generated mainly small rod-shaped (Cu,Ni)6Sn5 intermetallic compounds (IMCs) inside the β-Sn phase. Moreover, increasing the Ag content and adding Ni could result in the change of the shape and size of the IMC precipitate. Hence, a significant improvement is observed in the mechanical properties of SAC solders with increasing Ag content and Ni addition. On the other hand, the tensile results of Ni-doped SAC solders showed that both the yield stress and ultimate tensile strengths decrease with increasing temperature and with decreasing strain rate. This behavior was attributed to the competing effects of work hardening and dynamic recovery processes. The Sn-2.0Ag-0.5Cu-0.05Ni solder displayed the highest mechanical properties due to the formation of hard (Cu,Ni)6Sn5 IMCs. Based on the obtained stress exponents and activation energies, it is suggested that the dominant deformation mechanism in SAC (205)-, SAC (0505)- and SAC (0505)-0.05Ni solders is pipe diffusion, and lattice self-diffusion in SAC (205)-0.05Ni solder. In view of these results, the Sn-2.0Ag-0.5Cu-0.05Ni alloy is a more reliable solder alloy with improved properties compared with other solder alloys tested in the present work.

Gas atomization of Cu-modified AB5 metal hydride alloys

International Nuclear Information System (INIS)

Young, K.; Ouchi, T.; Banik, A.; Koch, J.; Fetcenko, M.A.; Bendersky, L.A.; Wang, K.; Vaudin, M.

2011-01-01

Research highlights: → The gas atomization process together with a hydrogen annealing process was demonstrated on AB5 alloys. → The method was found to be effective in restoring the original cycle life sacrificed by the incorporation of copper in the alloy formula as a means of improving the low temperature performance of AB 5 alloys. → The new process also improves high rate, low temperature, and charge retention performances for both Cu-free and Cu-containing AB 5 alloys. - Abstract: Gas atomization together with a hydrogen annealing process has been proposed as a method to achieve improved low-temperature performance of AB 5 alloy electrodes in Ni/MH batteries and restore the original cycle life which was sacrificed by the incorporation of copper in the alloy formula. While the gas atomization process reduces the lattice constant aspect ratio c/a of the Cu-containing alloys, the addition of a hydrogen annealing step recovers this property, although it is still inferior to the conventionally prepared annealed Cu-free alloy. This observation correlates very well with the cycle life performance. In addition to extending the cycle life of the Cu-containing metal hydride electrode, processing by gas atomization with additional hydrogen annealing improves high-rate, low-temperature, and charge retention performances for both Cu-free and Cu-containing AB 5 alloys. The degradation mechanisms of alloys made by different processes through cycling are also discussed.

Stability of nanosized alloy thin films: Faulting and phase separation in metastable Ni/Cu/Ag-W films

International Nuclear Information System (INIS)

Csiszár, G.; Kurz, S.J.B.; Mittemeijer, E.J.

2016-01-01

A comparative study of Me(=Ni/Cu/Ag)-based, W-alloyed, nanocrystalline, heavily faulted thin films was carried out to identify parameters stabilizing the nanocrystalline nature upon thermal treatment. The three systems, initially of comparably, heavily twinned (twin boundaries at spacings of 1–5 nm) microstructures showed similarities but also strikingly different behaviours upon annealing, as observed by application of in particular X-ray diffraction (line-broadening) analysis and (high resolution) transmission electron microscopy. During annealing in the range of 30–600 °C, (i) segregation at the planar faults (for Me = Ni) and at grain boundaries (for Me = Ni,Cu,Ag), as well as nanoscale phase separation (for Me = Cu,Ag) take place, (ii) distinct grain growth does not occur and (iii) the twin boundaries either are largely preserved ((Ni(W) and Ag(W)) or disappear totally (Cu(W))), which was ascribed to an altered faulting energy, due to change of the amount of W segregated at the twin boundaries, and to the evolution of nano-precipitates. The nanosized films exhibit very large internal (macro)stresses parallel to the surface, which change during annealing in the range of 1 GPa (tensile) to −3 GPa (compressive) and thus are sensitive to the microstructural changes in the films (decomposition and relaxation) that happen on a nanoscale. The results are discussed in terms of thermodynamic and/or kinetic constraints controlling these processes and thus the thermal stability of the systems concerned.

Effect of alloying elements on the stability of Ni2M in Alloy690 based upon thermodynamic calculation

International Nuclear Information System (INIS)

Horiuchi, Toshiaki; Kuwano, Kazuhiro; Satoh, Naohiro

2012-01-01

Some researchers recently point out that Ni based alloys used in nuclear power plants have the ordering tendency, which is a potential to decrease mechanical properties within the expected lifetime of the plants. In the present study, authors evaluated the effect of 8 alloying elements on the ordering tendency in Alloy690 based upon thermodynamic calculation by Thermo-Calc. It is clarified that the additive amount of Fe, Cr, Ti and Si, particularly Fe and Cr, was influential for the stability of Ni 2 M, while that of Mn, Cu, B and C had almost no effect for that. Authors therefore designed the Ni 2 M stabilized alloy by no addition of Fe in Alloy690. Ni 2 M is estimated to be stable even at 773 K in the Ni 2 M stabilized alloy. The influence by long range ordering or precipitating of Ni 2 M in Alloy690 for mechanical properties or SCC susceptibility is expected to be clarified by the sample obtained in the present study. (author)

Giant magnetocaloric effect from reverse martensitic transformation in Ni–Mn–Ga–Cu ferromagnetic shape memory alloys

International Nuclear Information System (INIS)

Sarkar, Sudip Kumar; Sarita; Babu, P.D.; Biswas, Aniruddha; Siruguri, Vasudeva; Krishnan, Madangopal

2016-01-01

In an effort to produce Giant Magnetocaloric effect (GMCE) near room temperature, in a first ever such study, the austenite transformation temperature (A_s) was fine tuned to ferromagnetic Curie temperature (T_C) in Ferromagnetic Shape Memory Alloys (FSMA) and a large GMCE of ΔSM = −81.8 J/Kg-K was achieved in Ni_5_0Mn_1_8_._5Cu_6_._5Ga_2_5 alloy during reverse martensitic transformation (heating cycle) for a magnetic field change of 9 T at 303 K. Fine tuning of A_s with T_C was achieved by Cu substitution in Ni_5_0Mn_2_5_−_xCu_xGa_2_5 (0 ≤ x ≤ 7.0)-based FSMAs. Characterizations of these alloys were carried out using Optical and Scanning Electron Microscopy, X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC) and DC magnetization measurements. Addition of Cu to stoichiometric Heusler type Ni_2MnGa increases the martensitic transformation temperatures and decreases T_C. Concurrently, ΔSM increases with Cu addition and peaks at 6.5 at% Cu for which there is a virtual overlap between T_C and A_s. Maximum Refrigerant Capacity (RCP) of 327.0 J/Kg was also achieved in the heating cycle for 9 T field change at 303 K. Corresponding values for the cooling cycle measurements (measured during forward transformation) were 30.4 J/Kg-K and 123.5 J/Kg respectively for the same 6.5 at% Cu sample under the same thermo-magnetic conditions. - Highlights: • A_s was fine tuned to T_C in Cu substituted Ni_5_0Mn_2_5_−_xCu_xGa_2_5 (0 ≤ x ≤ 7.0) alloys. • MT temperature increases with Cu addition while T_C decreases. • A virtual overlapping of A_s with T_C was found in Ni_5_0Mn_1_8_._5Cu_6_._5Ga_2_5 alloys. • ΔSM = −81.8 J/Kg-K achieved from reverse MT for Δ(μ_0H) = 9 T at 303 K. • A highest RCP value of 94.6 J/Kg was observed for Δ(μ_0H) = 5 T in Cu:6.5 alloys.

Effect of test temperature and strain rate on the tensile properties of high-strength, high-conductivity copper alloys

Energy Technology Data Exchange (ETDEWEB)

Zinkle, S.J.; Eatherly, W.S. [Oak Ridge National Lab., TN (United States)

1997-04-01

The unirradiated tensile properties of wrought GlidCop AL25 (ITER grade zero, IGO) solutionized and aged CuCrZr, and cold-worked and aged and solutionized and aged Hycon 3HP{trademark} CuNiBe have been measured over the temperature range of 20-500{degrees}C at strain rates between 4 x 10{sup {minus}4} s{sup {minus}1} and 0.06 s{sup {minus}1}. The measured room temperature electrical conductivity ranged from 64 to 90% IACS for the different alloys. All of the alloys were relatively insensitive to strain rate at room temperature, but the strain rate sensitivity of GlidCop Al25 increased significantly with increasing temperature. The CuNiBe alloys exhibited the best combination of high strength and high conductivity at room temperature. The strength of CuNiBe decreased slowly with increasing temperature. However, the ductility of CuNiBe decreased rapidly with increasing temperature due to localized deformation near grain boundaries, making these alloy heats unsuitable for typical structural applications above 300{degrees}C. The strength and uniform elongation of GlidCop Al25 decreased significantly with increasing temperature at a strain rate of 1 x 10{sup {minus}3} s{sup {minus}1}, whereas the total elongation was independent of test temperature. The strength and ductility of CuCrZr decreased slowly with increasing temperature.

Thermophysical Properties Measurements of Zr62Cu20Al10Ni8

Science.gov (United States)

Bradshaw, Richard C.; Waren, Mary; Rogers, Jan R.; Rathz, Thomas J.; Gangopadhyay, Anup K.; Kelton, Ken F.; Hyers, Robert W.

2006-01-01

Thermophysical property studies performed at high temperature can prove challenging because of reactivity problems brought on by the elevated temperatures. Contaminants from measuring devices and container walls can cause changes in properties. To prevent this, containerless processing techniques can be employed to isolate a sample during study. A common method used for this is levitation. Typical levitation methods used for containerless processing are, aerodynamically, electromagnetically and electrostatically based. All levitation methods reduce heterogeneous nucleation sites, 'which in turn provide access to metastable undercooled phases. In particular, electrostatic levitation is appealing because sample motion and stirring are minimized; and by combining it with optically based non-contact measuring techniques, many thermophysical properties can be measured. Applying some of these techniques, surface tension, viscosity and density have been measured for the glass forming alloy Zr62Cu20Al10Ni8 and will be presented with a brief overview of the non-contact measuring method used.

New ternary ordered structures in CuMPt6 (M=3d elements) alloys

International Nuclear Information System (INIS)

Das, Ananda Kumar; Nakamura, Reo; Takahashi, Miwako; Ohshima, Ken-ichi; Iwasaki, Hiroshi; Shishido, Toetsu

2006-01-01

X-ray and electron diffraction measurements were performed to investigate the structure and ordering behaviour of the ternary alloys CuMPt 6 (M=Ti, V, Cr, Mn, Fe, Co, and Ni). X-ray polycrystalline diffraction patterns of all the speciments quenched from 1000degC have shown that a single phase is formed at this stoichiometric composition. The alloys with M=Cr, Mn, Co, and Ni have the face-centred cubic (fcc) structure, while in the alloys with M=Ti, V, and Fe ordering has occurred and the structure is of the Cu 3 Au type. On annealing at lower temperatures ordering has been induced in the alloys with M=Cr, Mn, and Co and the structure is of the Cu 3 Au type, though the ordering in the last alloy has remained incomplete. Detailed X-ray diffraction measurements on single crystals of the CuMnPt 6 alloy have revealed that further ordering takes place and structure changes from the Cu 3 Au type into the cubic ABC 6 type with the unit cell as large 2 x 2 x 2 as the fcc unit cell, a new observation of the double-step ordering in the ternary fcc alloy. The corresponding transition temperatures are T c =970(±5)degC and T cl =750(±5)degC. (author)

Nonlinear elastic properties of bulk metallic glasses Zr52.5Ti5Cu17.9Ni14.6Al10 and Pd40Cu30Ni10P20

International Nuclear Information System (INIS)

Kobelev, N.P.; Kolyvanov, E.L.; Khonik, V.A.

2005-01-01

The influence of uniaxial compression on the propagation of ultrasonic vibrations in Zr 52.5 Ti 5 Cu 17.9 Ni 14.6 Al 10 and Pd 40 Cu 30 Ni 10 P 20 bulk metallic glasses produced by melt quenching at a rate of 100 K/s is investigated. Elastic deformation was realized by compression of the samples along their long axis up to strains of about 1 GPa. Deriving of major ratios used during the calculation of the third-order elastic moduli of the glasses is described in brief, the results of the calculations being provided. A qualitative agreement between the calculated results and available data on the influence of the uniform pressure on the sound wave propagation rate was obtained [ru

Internal friction behaviours in Zr57Al10Ni12.4Cu15.6Nb5 bulk metallic glass

International Nuclear Information System (INIS)

Zhang Bo; Zu Fangqiu; Zhen Kang; Shui Jiapeng; Wen Ping

2002-01-01

The internal friction patterns of Zr 57 Al 10 Ni 12.4 Cu 15.6 Nb 5 bulk metallic glass (BMG) were investigated with different frequencies and heating rates. An internal friction peak with extremely large magnitude is observed in the internal friction curves as a function of temperature (Q -1 -T curves). The internal friction peak was fitted by an equation Q -1 =AX(T)/η, where A is a constant, X(T) is the fraction of the glass/supercooled liquid and the viscosity η obeys the Vogel-Fulcher-Tammann relation. We confirm that the internal friction peak originates from both of the glass transition and crystallization. The anomalous behaviours of the peak suggest that Zr 57 Al 10 Ni 12.4 Cu 15.6 Nb 5 BMG has a wide supercooled liquid region and the magnitude of the peak can be used to judge the glass forming ability (GFA) of the glass forming alloys. In addition, the internal friction technique proved to be a new powerful tool for studying structural relaxation and phase transition as well as the GFA of BMG. (author)

Microstructure and mechanical properties of Al-20Si-5Fe-2X (X = Cu, Ni, Cr) alloys produced by melt-spinning

International Nuclear Information System (INIS)

Rajabi, M.; Simchi, A.; Davami, P.

2008-01-01

Al-20Si-5Fe-2X (X = Cu, Ni and Cr) ribbons were produced by melt-spinning and consolidated by hot pressing at 400 deg. C for 60 min. The microstructure of the ribbons and the consolidated alloys was investigated using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffractometry (XRD) method, and transmission electron microscopy (TEM). The hardness and compressive strength of the specimens at ambient and elevated temperatures were examined. The microstructure of the ribbons exhibited featureless and dendritic zones. Results of XRD and TEM showed formation of spherically shaped Si particles with an average diameter of 20 nm. Ultrafine Si (110-150 nm) and iron-containing intermetallic particles were noticed in the microstructure of the consolidated ribbons. An improved strength was achieved by alloying of Al-20Si-5Fe with Cu, Ni, and Cr. Nickel was found to be the most effective element in increasing the maximum stress, particularly at elevated temperatures

Effect of the third element on the structure of liquid Mg{sub 65}Cu{sub 25}Y{sub 10} alloy

Energy Technology Data Exchange (ETDEWEB)

Liu, Dan [Key Laboratory for Liquid–Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061 (China); Weihai Wanfeng Magnesium Industry Science and Technology Development Co. Ltd., Weihai 264209 (China); Zhu, Xun Ming [Weihai Wanfeng Magnesium Industry Science and Technology Development Co. Ltd., Weihai 264209 (China); Qin, Jing Yu, E-mail: qinjy@sdu.edu.cn [Key Laboratory for Liquid–Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061 (China); Duan, Jun Peng; Wang, Ai Min [Weihai Wanfeng Magnesium Industry Science and Technology Development Co. Ltd., Weihai 264209 (China); Gu, Ting Kun [School of Electrical Engineering, Shandong University, Jinan 250061 (China)

2016-08-12

The liquid structures of Mg{sub 65}Cu{sub 25}Y{sub 10} and its three homologous binary liquid alloys are investigated via ab initio molecular dynamics in the present work. The chemical and topological environments in all four liquid alloys are analyzed using pair distribution function, coordination number, and the Voronoi polyhedron. It shows that the Cu atoms play significant role in deciding the chemical and topological short-range orders of the Mg{sub 65}Cu{sub 25}Y{sub 10} liquid alloy. The Voronoi polyhedra in the ternary liquid alloy illustrate less varieties and longer lifetime. Moreover, the diffusion coefficients are decreased significantly in the ternary liquid alloys according to the mean square displacements. All above offer a deeper insight into how the three species work in the Mg{sub 65}Cu{sub 25}Y{sub 10} liquid alloy. - Highlights: • Cu plays crucial role in Mg{sub 65}Cu{sub 25}Y{sub 10}'s chemical and topological SROs. • Additive elements decrease varieties and prolong lifetimes of Voronoi polyhedra. • Additive elements hinder the diffusion of Mg and Y efficiently.

Development of a tungsten heavy alloy, W-Ni-Mn, used as kinetic energy penetrator

International Nuclear Information System (INIS)

Zahraee, S. M.; Salehi, M. T.; Arabi, H.; Tamizifar, M.

2007-01-01

The objective of this research was to develop a tungsten heavy alloy having a microstructure and properties good enough to penetrate hard rolled steels as deep as possible. In addition this alloy should not have environmental problems as depleted uranium materials, For this purpose a wide spread literature survey was performed and on the base of information obtained in this survey, three compositions of tungsten heavy alloy were chosen for investigation in this research. The alloys namely 90 W-7 Ni-3 Fe, 90 W-9 Ni-Mn and 90 W-8 Ni-2 Mn were selected and after producing these alloys through powder metallurgy technique, their thermal conductivity, compression flow properties and microstructure, were studied. The results of these investigations indicated that W-Ni-Mn alloys had better flow properties and lower thermal conductivities relative to W-Ni-Fe alloy. In addition Mn helped to obtain a finer microstructure in tungsten heavy alloy. Worth mentioning that a finer microstructure as well as lower thermal conductivity in this type of alloys increased the penetration depth due to formation of adiabatic shear bands during impact

Effect of solute elements in Ni alloys on blistering under He + and D + ion irradiation

Science.gov (United States)

Wakai, E.; Ezawa, T.; Takenaka, T.; Imamura, J.; Tanabe, T.; Oshima, R.

2007-08-01

Effects of solute atoms on microstructural evolution and blister formation have been investigated using Ni alloys under 25 keV He + and 20 keV D + irradiation at 500 °C to a dose of about 4 × 10 21 ions/m 2. The specimens used were pure Ni, Ni-Si, Ni-Co, Ni-Cu, Ni-Mn and Ni-Pd alloys. The volume size factors of solute elements for the Ni alloys range from -5.8% to +63.6%. The formations of blisters were observed in the helium-irradiated specimens, but not in the deuteron-irradiated specimens. The areal number densities of blisters increased with volume size difference of solute atoms. The dependence of volume size on the areal number densities of blisters was very similar to that of the number densities of bubbles on solute atoms. The size of the blisters inversely decreased with increasing size of solute atoms. The formation of blisters was intimately related to the bubble growth, and the gas pressure model for the formation of blisters was supported by this study.

Search for positron localization near transition-metal solutes of negative effective charge in Ni and Cu

International Nuclear Information System (INIS)

Hunter, D.M.; Grynszpan, R.I.; Arrott, A.S.

1993-01-01

Results of an early (1973) angular correlation (ACAR) study of dilute (0.5 at.%) Cu based alloys by a Japanese group were interpreted in terms of an attraction of e + by transition metal solutes of effective negative charge. Doppler Broadening (DB) measurements reveal no such an effect for Cu(Mn) and Cu(Ni) solid solutions as well as for Ni alloys with 3d, 4d and 5d transition metal solutes (0.1 to 1.5 at.%) i.e. no evidence of e + localization near these impurities is seen. Our results strongly suggest that the ACAR results are due to the metallurgical state of the samples. In contrast, significant DB lineshape parameter variations, observed for our Ni(Zr) alloys, are attributed to positron trapping in and near Ni 5 Zr precipitates. Our DB results for a series of Ni(Au) alloys are understood in terms of a combination of the effect of an overall lattice expansion and a positron preference for clusters of Au atoms. The above comparison between DB and ACAR results is supported by our 'spin polarized' DB results for a (001) Ni single crystal which resemble those obtained by other groups using a 'spin polarized' 2D-ACAR technique. (orig.)

Modelling radiation-induced phase changes in binary FeCu and ternary FeCuNi alloys using an artificial intelligence-based atomistic kinetic Monte Carlo approach

Science.gov (United States)

Castin, N.; Malerba, L.; Bonny, G.; Pascuet, M. I.; Hou, M.

2009-09-01

We apply a novel atomistic kinetic Monte Carlo model, which includes local chemistry and relaxation effects when assessing the migration energy barriers of point defects, to the study of the microchemical evolution driven by vacancy diffusion in FeCu and FeCuNi alloys. These alloys are of importance for nuclear applications because Cu precipitation, enhanced by the presence of Ni, is one of the main causes of hardening and embrittlement in reactor pressure vessel steels used in existing nuclear power plants. Local chemistry and relaxation effects are introduced using artificial intelligence techniques, namely a conveniently trained artificial neural network, to calculate the migration energy barriers of vacancies as functions of the local atomic configuration. We prove, through a number of results, that the use of the neural network is fully equivalent to calculating the migration energy barriers on-the-fly, using computationally expensive methods such as nudged elastic bands with an interatomic potential. The use of the neural network makes the computational cost affordable, so that simulations of the same type as those hitherto carried out using heuristic formulas for the assessment of the energy barriers can now be performed, at the same computational cost, using more rigorously calculated barriers. This method opens the way to properly treating more complex problems, such as the case of self-interstitial cluster formation, in an atomistic kinetic Monte Carlo framework.

Modelling radiation-induced phase changes in binary FeCu and ternary FeCuNi alloys using an artificial intelligence-based atomistic kinetic Monte Carlo approach

International Nuclear Information System (INIS)

Castin, N.; Malerba, L.; Bonny, G.; Pascuet, M.I.; Hou, M.

2009-01-01

We apply a novel atomistic kinetic Monte Carlo model, which includes local chemistry and relaxation effects when assessing the migration energy barriers of point defects, to the study of the microchemical evolution driven by vacancy diffusion in FeCu and FeCuNi alloys. These alloys are of importance for nuclear applications because Cu precipitation, enhanced by the presence of Ni, is one of the main causes of hardening and embrittlement in reactor pressure vessel steels used in existing nuclear power plants. Local chemistry and relaxation effects are introduced using artificial intelligence techniques, namely a conveniently trained artificial neural network, to calculate the migration energy barriers of vacancies as functions of the local atomic configuration. We prove, through a number of results, that the use of the neural network is fully equivalent to calculating the migration energy barriers on-the-fly, using computationally expensive methods such as nudged elastic bands with an interatomic potential. The use of the neural network makes the computational cost affordable, so that simulations of the same type as those hitherto carried out using heuristic formulas for the assessment of the energy barriers can now be performed, at the same computational cost, using more rigorously calculated barriers. This method opens the way to properly treating more complex problems, such as the case of self-interstitial cluster formation, in an atomistic kinetic Monte Carlo framework.

Modelling radiation-induced phase changes in binary FeCu and ternary FeCuNi alloys using an artificial intelligence-based atomistic kinetic Monte Carlo approach

Energy Technology Data Exchange (ETDEWEB)

Castin, N. [Structural Materials Group, Nuclear Materials Science Institute, Kernenergie Centre d' Etude de l' Energie Nucleaire (SCK CEN), Studiecentrum voor, Boeretang 200, 2400 Mol (Belgium); Physique des Solides Irradies et des Nanostructures (PSIN), Universite Libre de Bruxelles (ULB), Boulevard du Triomphe CP234, 1050 Brussels (Belgium); Malerba, L. [Structural Materials Group, Nuclear Materials Science Institute, Kernenergie Centre d' Etude de l' Energie Nucleaire (SCK CEN), Studiecentrum voor, Boeretang 200, 2400 Mol (Belgium)], E-mail: lmalerba@sckcen.be; Bonny, G. [Structural Materials Group, Nuclear Materials Science Institute, Kernenergie Centre d' Etude de l' Energie Nucleaire (SCK CEN), Studiecentrum voor, Boeretang 200, 2400 Mol (Belgium); Laboratory of Theoretical Physics, Universiteit Gent, Proeftuinstraat 86, B-9000 Gent (Belgium); Pascuet, M.I. [Structural Materials Group, Nuclear Materials Science Institute, Kernenergie Centre d' Etude de l' Energie Nucleaire (SCK CEN), Studiecentrum voor, Boeretang 200, 2400 Mol (Belgium); CAC-CNEA, Departamento de Materiales, Avda. Gral. Paz 1499, 1650 San Martin, Pcia. Buenos Aires (Argentina); CONICET, Avda. Rivadavia 1917, 1033 Buenos Aires (Argentina); Hou, M. [Physique des Solides Irradies et des Nanostructures (PSIN), Universite Libre de Bruxelles (ULB), Boulevard du Triomphe CP234, 1050 Brussels (Belgium)

2009-09-15

We apply a novel atomistic kinetic Monte Carlo model, which includes local chemistry and relaxation effects when assessing the migration energy barriers of point defects, to the study of the microchemical evolution driven by vacancy diffusion in FeCu and FeCuNi alloys. These alloys are of importance for nuclear applications because Cu precipitation, enhanced by the presence of Ni, is one of the main causes of hardening and embrittlement in reactor pressure vessel steels used in existing nuclear power plants. Local chemistry and relaxation effects are introduced using artificial intelligence techniques, namely a conveniently trained artificial neural network, to calculate the migration energy barriers of vacancies as functions of the local atomic configuration. We prove, through a number of results, that the use of the neural network is fully equivalent to calculating the migration energy barriers on-the-fly, using computationally expensive methods such as nudged elastic bands with an interatomic potential. The use of the neural network makes the computational cost affordable, so that simulations of the same type as those hitherto carried out using heuristic formulas for the assessment of the energy barriers can now be performed, at the same computational cost, using more rigorously calculated barriers. This method opens the way to properly treating more complex problems, such as the case of self-interstitial cluster formation, in an atomistic kinetic Monte Carlo framework.

Theoretical analysis of experimental tracer and interdiffusion data in Cu-Ni-Fe alloys

International Nuclear Information System (INIS)

Belova, I.V.; Murch, G.E.; Filipek, R.; Danielewski, M.

2005-01-01

In this paper, we present strategies to extract fundamental atomistic information from measured diffusion coefficients in a ternary alloy system. The strategies are exemplified with Cu-Ni-Fe alloys at 1271 K where recent extensive interdiffusion coefficients and tracer diffusion coefficients for all three components have become available. We develop new defining phenomenological expressions for the vacancy-wind factors in terms of the diffusion coefficients. We show that the measured tracer diffusion coefficients can be processed using the Manning and Moleko, Allnatt and Allnatt random alloy diffusion kinetics formalisms (with and without the assumption of the Gibbs-Duhem relation between the thermodynamic activities) to give jump frequencies, tracer correlation factors, vacancy-wind factors and phenomenological coefficients. It is shown for example that Cu is generally the most correlated component in its diffusion behavior and that the off-diagonal phenomenological coefficients can be as high as 64% of the smallest of the diagonal phenomenological coefficients. It is also shown that the Darken formalism (which ignores off-diagonal phenomenological coefficients) is in fact a reasonable approximation for expressing the diagonal phenomenological coefficients in terms of the tracer diffusion coefficients. It is then shown how the measured interdiffusivities can be processed with these formalisms to give tracer diffusivities, vacancy-wind factors and phenomenological coefficients. Finally, we show how a straightforward strategy starting with the Darken analysis that is then followed by the Manning or Moleko, Allnatt and Allnatt analysis can be used to gain access to the vacancy-wind factors and the off-diagonal phenomenological coefficients

Crystallization of Pd40CU30Ni10P20 bulk metallic glass with and without pressure

DEFF Research Database (Denmark)

Yang, B.; Jiang, Jianzhong; Zhuang, Yanxin

2007-01-01

The glass-transition behavior of Pd40Cu30Ni10P20 bulk metallic glass was investigated by differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD). The effect of pressure on the crystallization behavior of Pd40Cu30Ni10P20 bulk glass was studied by in situ high-pressure and high...

Microstructural evolution under high flux irradiation of dilute Fe-CuNiMnSi alloys studied by an atomic kinetic Monte Carlo model accounting for both vacancies and self interstitials

International Nuclear Information System (INIS)

Vincent, E.; Becquart, C.S.; Domain, C.

2008-01-01

Under neutron irradiation, a large amount of point defects (vacancies and interstitials) are created. In the irradiated pressure vessel steels, weakly alloyed, these point defects are responsible for the diffusion of the solute atoms, leading to the formation of solute rich precipitates within the matrix. Ab initio calculations based on the density functional theory have been performed to determine the interactions of point defects with solute atoms in dilute FeX alloys (X = Cu, Mn, Ni or Si). For Mn, the results of these calculations lead to think that solute transport in α-Fe can very likely take place through an interstitial mechanism as well as via vacancies while the other solutes (Cu, Ni and Si) which establish strong bonds with vacancies diffuse more likely via vacancies only. The database thus created has been used to parameterize an atomic kinetic Monte Carlo model taking into account both vacancies and interstitials. Some results of irradiation damage in dilute Fe-CuNiMnSi alloys obtained with this model will be presented

Microstructural evolution under high flux irradiation of dilute Fe CuNiMnSi alloys studied by an atomic kinetic Monte Carlo model accounting for both vacancies and self interstitials

Science.gov (United States)

Vincent, E.; Becquart, C. S.; Domain, C.

2008-12-01

Under neutron irradiation, a large amount of point defects (vacancies and interstitials) are created. In the irradiated pressure vessel steels, weakly alloyed, these point defects are responsible for the diffusion of the solute atoms, leading to the formation of solute rich precipitates within the matrix. Ab initio calculations based on the density functional theory have been performed to determine the interactions of point defects with solute atoms in dilute FeX alloys (X = Cu, Mn, Ni or Si). For Mn, the results of these calculations lead to think that solute transport in α-Fe can very likely take place through an interstitial mechanism as well as via vacancies while the other solutes (Cu, Ni and Si) which establish strong bonds with vacancies diffuse more likely via vacancies only. The database thus created has been used to parameterize an atomic kinetic Monte Carlo model taking into account both vacancies and interstitials. Some results of irradiation damage in dilute Fe-CuNiMnSi alloys obtained with this model will be presented.

Corrosion aspects of Ni-Cr-Fe based and Ni-Cu based steam generator tube materials

International Nuclear Information System (INIS)

Dutta, R.S.

2009-01-01

This paper reviews corrosion related issues of Ni-Cr-Fe based (in a general sense) and Ni-Cu based steam generator tube materials for nuclear power plants those have been dealt with for last more than four decades along with some updated information on corrosion research. The materials include austenitic stainless steels (SSs), Alloy 600, Monel 400, Alloy 800 and Alloy 690. Compatibility related issues of these alloys are briefly discussed along with the alloy chemistry and microstructure. For austenitic SSs, stress corrosion cracking (SCC) behaviour in high temperature aqueous environments is discussed. For Alloy 600, intergranular cracking in high temperature water including hydrogen-induced intergranular cracking is highlighted along with the interactions of material in various environments. In case of Monel 400, intergranular corrosion and pitting corrosion at ambient temperature and SCC behaviour at elevated temperature are briefly described. For Alloy 800, the discussion covers SCC behaviour, surface characterization and microstructural aspects of pitting, whereas hydrogen-related issues are also highlighted for Alloy 690.

Growth of intermetallics between Sn/Ni/Cu, Sn/Ag/Cu and Sn/Cu layered structures

International Nuclear Information System (INIS)

Horváth, Barbara; Illés, Balázs; Shinohara, Tadashi

2014-01-01

Intermetallic growth mechanisms and rates are investigated in Sn/Ni/Cu, Sn/Ag/Cu and Sn/Cu layer systems. An 8–10 μm thick Sn surface finish layer was electroplated onto a Cu substrate with a 1.5–2 μm thick Ni or Ag barrier layer. In order to induce intermetallic layer growth, the samples were aged in elevated temperatures: 50 °C and 125 °C. Intermetallic layer growth was checked by focused ion beam–scanning ion microscope. The microstructures and chemical compositions of the intermetallic layers were observed with a transmission electron microscope. It has been found that Ni barrier layers can effectively block the development of Cu 6 Sn 5 intermetallics. The intermetallic growth characteristics in the Sn/Cu and Sn/Ni/Cu systems are very similar. The intermetallic layer grows towards the Sn layer and forms a discrete layer. Differences were observed only in the growth gradients and surface roughness of the intermetallic layer which may explain the different tin whiskering properties. It was observed that the intermetallic layer growth mechanisms are completely different in the Ag barrier layers compared to the Ni layers. In the case of Sn/Ag/Cu systems, the Sn and Cu diffused through the Ag layer, formed Cu 6 Sn 5 intermetallics mainly at the Sn/Ag interface and consumed the Ag barrier layer. - Highlights: • Intermetallic growth was characterised in Sn/Ni/Cu, Sn/Ag/Cu and Sn/Cu layer systems. • Intermetallic growth rates and roughness are similar in the Sn/Cu and Sn/Ni/Cu systems. • Sn/Ni/Cu system contains the following intermetallic layer structure Sn–Ni3Sn4–Ni3Sn2–Ni3Sn–Ni. • In the case of Sn/Ag/Cu systems the Sn and Cu diffusion consumes the Ag barrier layer. • When Cu reaches the Sn/Ag interface a large amount of Cu 6 Sn 5 forms above the Ag layer

Soldering-induced Cu diffusion and intermetallic compound formation between Ni/Cu under bump metallization and SnPb flip-chip solder bumps

Science.gov (United States)

Huang, Chien-Sheng; Jang, Guh-Yaw; Duh, Jenq-Gong

2004-04-01

Nickel-based under bump metallization (UBM) has been widely used as a diffusion barrier to prevent the rapid reaction between the Cu conductor and Sn-based solders. In this study, joints with and without solder after heat treatments were employed to evaluate the diffusion behavior of Cu in the 63Sn-37Pb/Ni/Cu/Ti/Si3N4/Si multilayer structure. The atomic flux of Cu diffused through Ni was evaluated from the concentration profiles of Cu in solder joints. During reflow, the atomic flux of Cu was on the order of 1015-1016 atoms/cm2s. However, in the assembly without solder, no Cu was detected on the surface of Ni even after ten cycles of reflow. The diffusion behavior of Cu during heat treatments was studied, and the soldering-process-induced Cu diffusion through Ni metallization was characterized. In addition, the effect of Cu content in the solder near the solder/intermetallic compound (IMC) interface on interfacial reactions between the solder and the Ni/Cu UBM was also discussed. It is evident that the (Cu,Ni)6Sn5 IMC might form as the concentration of Cu in the Sn-Cu-Ni alloy exceeds 0.6 wt.%.

Diffusion behavior and atomic mobilities for fcc Cu–Cr–Ni alloys

International Nuclear Information System (INIS)

Xu, Gaochi; Liu, Yajun; Lei, Fuyue; Sheng, Guang; Kang, Zhitao

2015-01-01

In this work, diffusion couples of fcc Cu–Cr–Ni alloys annealed at 1373 K for 80 h are investigated. The interdiffusion coefficients are retrieved from common compositions of two diffusion couples, which are then combined with thermodynamic descriptions to explore atomic mobilities of Cu, Cr and Ni in fcc Cu–Cr–Ni alloys within the CALPHAD framework. In order to confirm the quality of such kinetic characteristics, a comparison between calculated and experimentally measured concentration profiles of diffusion couples and diffusion paths in Gibbs triangle is made, where the agreement is excellent. The results of this study contribute to the establishment of a general Ni-based mobility database for alloy design. - Highlights: • Atomic mobilities of fcc Cu–Cr–Ni phases were determined. • Experimental interdiffusivities were critically evaluated. • Main and cross interdiffusivities show their peculiarities. • The profiles reveal kinetic importance for alloy microstructures

Magnetic refrigeration capabilities of magnetocaloric Ni2Mn:75Cu:25Ga

Science.gov (United States)

Mishra, S. K.; Jenkins, C. A.; Dubenko, I.; Samanta, T.; Ali, N.; Roy, S.

2013-03-01

Doping-driven competition between energetically similar ground states leads to many exciting materials phenomena such as the emergence of high-Tc superconductivity, diluted magnetic semiconductors, and colossal magnetoresistance. Doped Ni2MnGa Heusler alloy, which is a multifunctional ferromagnetic alloy with various exotic physical properties demonstrates this notion of rich phenomenology via modified ground spin states. Adopting this generic concept, here we will present a novel doped Ni2Mn.75Cu.25Ga alloy that offers unprecedented co-existence of the magnetocaloric effect and fully controlled ferromagnetism at room temperature. Application of site engineering enables us to manipulate the ground spin state that leads to the decrease in magnetic transition temperature and also increases the delocalization of the Mn magnetism. SQUID magnetometery suggests that Cu doping enhances the saturation magnetization, coercive field and clarity of magnetic hysteresis loops. By exploiting x-ray absorption techniques and measuring element specific magnetic hysteresis loops, here we will describe the microscopic origin of enhnaced magnetocaloric properties and d-d interaction driven charge transfer effects in Ni2Mn.75Cu.25Ga This work was supported by DOE Grant No. DE-FG02-06ER46291

Constituent phase diagrams of the Al-Cu-Fe-Mg-Ni-Si system and their application to the analysis of aluminium piston alloys

Energy Technology Data Exchange (ETDEWEB)

Belov, N.A. [Moscow Institute of Steel and Alloys, Leninsky prosp. 4, Moscow 119049 (Russian Federation); Eskin, D.G. [Netherlands Institute for Metals Research, Rotterdamseweg 137, 2628AL Delft (Netherlands)]. E-mail: deskin@nimr.nl; Avxentieva, N.N. [Moscow Institute of Steel and Alloys, Leninsky prosp. 4, Moscow 119049 (Russian Federation)

2005-10-15

The evaluation of phase equilibria in quinary systems that constitute the commercially important Al-Cu-Fe-Mg-Ni-Si alloying system is performed in the compositional range of casting alloys by means of metallography, electron probe microanalysis, X-ray diffractometry, differential scanning calorimetry, and by the analysis of phase equilibria in the constituent systems of lesser dimensionality. Suggested phase equilibria are illustrated by bi-, mono- and invariant solidification reactions, polythermal diagrams of solidification, distributions of phase fields in the solid state, and isothermal and polythermal sections. Phase composition of as-cast alloys is analyzed in terms of non-equilibrium solidification. It is shown that the increase in copper concentration in piston Al-Si alloys results in the decrease in the equilibrium solidus from 540 to 505 deg C. Under non-equilibrium solidification conditions, piston alloys finish solidification at {approx}505 deg C. Iron is bound in the quaternary Al{sub 8}FeMg{sub 3}Si{sub 6} phase in low-iron alloys and in the ternary Al{sub 9}FeNi and Al{sub 5}FeSi phases in high-iron alloys.

Structure and Mechanical Properties of Al-Cu-Fe-X Alloys with Excellent Thermal Stability.

Science.gov (United States)

Školáková, Andrea; Novák, Pavel; Mejzlíková, Lucie; Průša, Filip; Salvetr, Pavel; Vojtěch, Dalibor

2017-11-05

In this work, the structure and mechanical properties of innovative Al-Cu-Fe based alloys were studied. We focused on preparation and characterization of rapidly solidified and hot extruded Al-Cu-Fe, Al-Cu-Fe-Ni and Al-Cu-Fe-Cr alloys. The content of transition metals affects mechanical properties and structure. For this reason, microstructure, phase composition, hardness and thermal stability have been investigated in this study. The results showed exceptional thermal stability of these alloys and very good values of mechanical properties. Alloying by chromium ensured the highest thermal stability, while nickel addition refined the structure of the consolidated alloy. High thermal stability of all tested alloys was described in context with the transformation of the quasicrystalline phases to other types of intermetallics.

Structural evolutions of the mechanically alloyed Al70Cu20Fe10 ...

Indian Academy of Sciences (India)

The i-phase was observed only for short-time milled powders after heat treatment above 600°C. The -phase was one of the major phases in the Al70Cu20Fe10 alloy. The w-Al7Cu2Fe1 phase (w-phase) was obtained only after heat treatment of the short-time milled and unmilled samples. The present investigation ...

Microstructural evolution of direct chill cast Al-15.5Si-4Cu-1Mg-1Ni-0.5Cr alloy during solution treatment

OpenAIRE

He Kezhun; Yu Fuxiao; Zhao Dazhi

2011-01-01

Heat treatment has important influence on the microstructure and mechanical properties of Al-Si alloys. The most common used heat treatment method for these alloys is solution treatment followed by age-hardening. This paper investigates the microstructural evolution of a direct chill (DC) cast Al-15.5Si-4Cu-1Mg-1Ni-0.5Cr alloy after solution treated at 500, 510, 520 and 530℃, respectively for different times. The major phases observed in the as-cast alloy are α-aluminum dendrite, primary Si p...

Giant magnetocaloric effect from reverse martensitic transformation in Ni–Mn–Ga–Cu ferromagnetic shape memory alloys

Energy Technology Data Exchange (ETDEWEB)

Sarkar, Sudip Kumar, E-mail: sudips@barc.gov.in [Glass and Advanced Materials Division, Bhabha Atomic Research Centre, Mumbai, 400085 (India); Sarita [Glass and Advanced Materials Division, Bhabha Atomic Research Centre, Mumbai, 400085 (India); Babu, P.D. [UGC-DAE Consortium for Scientific Research, Mumbai Centre, BARC, Mumbai, 400085 (India); Biswas, Aniruddha [Glass and Advanced Materials Division, Bhabha Atomic Research Centre, Mumbai, 400085 (India); Siruguri, Vasudeva [UGC-DAE Consortium for Scientific Research, Mumbai Centre, BARC, Mumbai, 400085 (India); Krishnan, Madangopal [Glass and Advanced Materials Division, Bhabha Atomic Research Centre, Mumbai, 400085 (India)

2016-06-15

In an effort to produce Giant Magnetocaloric effect (GMCE) near room temperature, in a first ever such study, the austenite transformation temperature (A{sub s}) was fine tuned to ferromagnetic Curie temperature (T{sub C}) in Ferromagnetic Shape Memory Alloys (FSMA) and a large GMCE of ΔSM = −81.8 J/Kg-K was achieved in Ni{sub 50}Mn{sub 18.5}Cu{sub 6.5}Ga{sub 25} alloy during reverse martensitic transformation (heating cycle) for a magnetic field change of 9 T at 303 K. Fine tuning of A{sub s} with T{sub C} was achieved by Cu substitution in Ni{sub 50}Mn{sub 25−x}Cu{sub x}Ga{sub 25} (0 ≤ x ≤ 7.0)-based FSMAs. Characterizations of these alloys were carried out using Optical and Scanning Electron Microscopy, X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC) and DC magnetization measurements. Addition of Cu to stoichiometric Heusler type Ni{sub 2}MnGa increases the martensitic transformation temperatures and decreases T{sub C}. Concurrently, ΔSM increases with Cu addition and peaks at 6.5 at% Cu for which there is a virtual overlap between T{sub C} and A{sub s}. Maximum Refrigerant Capacity (RCP) of 327.0 J/Kg was also achieved in the heating cycle for 9 T field change at 303 K. Corresponding values for the cooling cycle measurements (measured during forward transformation) were 30.4 J/Kg-K and 123.5 J/Kg respectively for the same 6.5 at% Cu sample under the same thermo-magnetic conditions. - Highlights: • A{sub s} was fine tuned to T{sub C} in Cu substituted Ni{sub 50}Mn{sub 25−x}Cu{sub x}Ga{sub 25} (0 ≤ x ≤ 7.0) alloys. • MT temperature increases with Cu addition while T{sub C} decreases. • A virtual overlapping of A{sub s} with T{sub C} was found in Ni{sub 50}Mn{sub 18.5}Cu{sub 6.5}Ga{sub 25} alloys. • ΔSM = −81.8 J/Kg-K achieved from reverse MT for Δ(μ{sub 0}H) = 9 T at 303 K. • A highest RCP value of 94.6 J/Kg was observed for Δ(μ{sub 0}H) = 5 T in Cu:6.5 alloys.

DO{sub 22}-(Cu,Ni){sub 3}Sn intermetallic compound nanolayer formed in Cu/Sn-nanolayer/Ni structures

Energy Technology Data Exchange (ETDEWEB)

Liu Lilin [School of Physics and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Huang, Haiyou [Department of Mechanical Engineering, Hong Kong University of Science and Technology (HKUST) (Hong Kong); Hong Kong - Beijing Joint Research Center, HKUST Fok Ying Tung Graduate School, Nansha, Guangzhou (China); Fu Ran; Liu Deming [ASM Assembly Automation Ltd. (Hong Kong); Zhang Tongyi, E-mail: mezhangt@ust.h [Department of Mechanical Engineering, Hong Kong University of Science and Technology (HKUST) (Hong Kong); Hong Kong - Beijing Joint Research Center, HKUST Fok Ying Tung Graduate School, Nansha, Guangzhou (China)

2009-11-03